US20100128678A1 - Adaptive coding and modulation for broadband data transmission - Google Patents

Adaptive coding and modulation for broadband data transmission Download PDF

Info

Publication number
US20100128678A1
US20100128678A1 US12/695,236 US69523610A US2010128678A1 US 20100128678 A1 US20100128678 A1 US 20100128678A1 US 69523610 A US69523610 A US 69523610A US 2010128678 A1 US2010128678 A1 US 2010128678A1
Authority
US
United States
Prior art keywords
modcode
packet
order
signal quality
data
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US12/695,236
Other versions
US8358657B2 (en
Inventor
William H. Thesling
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Viasat Inc
Original Assignee
Viasat Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Viasat Inc filed Critical Viasat Inc
Priority to US12/695,236 priority Critical patent/US8358657B2/en
Assigned to VIASAT, INC. reassignment VIASAT, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: THESLING, WILLIAM H.
Publication of US20100128678A1 publication Critical patent/US20100128678A1/en
Assigned to UNION BANK, N.A. reassignment UNION BANK, N.A. SECURITY AGREEMENT Assignors: VIASAT, INC.
Application granted granted Critical
Publication of US8358657B2 publication Critical patent/US8358657B2/en
Assigned to WILMINGTON TRUST, NATIONAL ASSOCIATION, AS COLLATERAL TRUSTEE reassignment WILMINGTON TRUST, NATIONAL ASSOCIATION, AS COLLATERAL TRUSTEE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: VIASAT, INC.
Assigned to BANK OF AMERICA, N.A. reassignment BANK OF AMERICA, N.A. SECURITY AGREEMENT Assignors: VIASAT, INC.
Assigned to BANK OF AMERICA, N.A., AS AGENT reassignment BANK OF AMERICA, N.A., AS AGENT SECURITY AGREEMENT Assignors: VIASAT, INC.
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H04L1/0003Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18539Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
    • H04B7/18543Arrangements for managing radio, resources, i.e. for establishing or releasing a connection for adaptation of transmission parameters, e.g. power control
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/18578Satellite systems for providing broadband data service to individual earth stations
    • H04B7/18582Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0009Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0015Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
    • H04L1/0016Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy involving special memory structures, e.g. look-up tables
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0015Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
    • H04L1/0019Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy in which mode-switching is based on a statistical approach
    • H04L1/0021Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy in which mode-switching is based on a statistical approach in which the algorithm uses adaptive thresholds
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0078Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
    • H04L1/0083Formatting with frames or packets; Protocol or part of protocol for error control
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/0008Modulated-carrier systems arrangements for allowing a transmitter or receiver to use more than one type of modulation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00Traffic control in data switching networks
    • H04L47/50Queue scheduling
    • H04L47/62Queue scheduling characterised by scheduling criteria
    • H04L47/6215Individual queue per QOS, rate or priority
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/02Channels characterised by the type of signal
    • H04L5/023Multiplexing of multicarrier modulation signals
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management
    • H04W72/12Wireless traffic scheduling
    • H04W72/1221Wireless traffic scheduling based on age of data to be sent
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0006Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format
    • H04L1/0007Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format by modifying the frame length
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0023Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
    • H04L1/0026Transmission of channel quality indication
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L2001/0092Error control systems characterised by the topology of the transmission link
    • H04L2001/0093Point-to-multipoint
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W28/00Network traffic management; Network resource management
    • H04W28/02Traffic management, e.g. flow control or congestion control
    • H04W28/10Flow control between communication endpoints
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management
    • H04W72/50Allocation or scheduling criteria for wireless resources
    • H04W72/54Allocation or scheduling criteria for wireless resources based on quality criteria
    • H04W72/542Allocation or scheduling criteria for wireless resources based on quality criteria using measured or perceived quality
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W80/00Wireless network protocols or protocol adaptations to wireless operation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W84/00Network topologies
    • H04W84/02Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04Large scale networks; Deep hierarchical networks
    • H04W84/06Airborne or Satellite Networks

Definitions

  • the present invention relates to wireless communications in general and, in particular, to adaptive coding and modulation.
  • Bi-directional wireless systems may benefit from the use of adaptive coding and modulation (“ACM”).
  • ACM adaptive coding and modulation
  • FEC Forward Error Correction
  • a return channel or other means may be used to report the conditions of a receiving terminal. These link conditions are often characterized by the individual user's (or terminal's) signal to noise ratio (“SNR”).
  • SNR signal to noise ratio
  • the waveform broadcast to a number of users includes data packets designated only for an individual terminal (or small group of terminals).
  • a message transmitted to a user requires fewer symbols (and thus less time) when a higher order modulation and higher code rate is used. Lower order modulation and lower code rate are more reliable but require more time to transmit the same size message.
  • each packet may be transmitted at an optimized modulation and coding (“modcode”) level given the destination terminal's link conditions.
  • Wireless channels may suffer from time varying channel conditions. Signals traveling in changing environmental conditions may be scattered, reflected, and diffracted, causing varying channel conditions over time. These changes may, for example, be due to changing weather conditions or movement of objects. There is a need for new ways to shape and control ACM data traffic dynamically, so that the traffic may be more efficiently transmitted to select terminals.
  • a process is described to build physical layer frames with a modcode adapted to the signal quality of a destination terminal.
  • Data packets assigned to the same modcode are generally sent in the same frame, although packets associated with higher modcodes may be used to complete a frame before switching to the applicable higher modcode for construction of subsequent frames.
  • an order of progression is restarted with an out of order packet above a threshold age.
  • Flow control filtering mechanisms and a variable reliability margin may be used to adapt dynamically to the current data traffic conditions.
  • packet forwarding queues are used to control the flow of packets according to modcode. Each queue is assigned to a different modcode, and is thereby associated with a signal quality range. Packets are placed into a queue associated with a signal quality range encompassing the link to which the packet is destined. In another set of embodiments, packets are associated with elements of a linked list. In such embodiments, the flow of packets is controlled by iterating through the linked list to identify packets within select signal quality ranges.
  • Various device and system configurations are described to implement the processes set forth above, as well.
  • FIG. 1 illustrates a satellite communications system in which adaptive coding and modulation (“ACM”) may be implemented according to various embodiments of the present invention.
  • ACM adaptive coding and modulation
  • FIG. 2A illustrates an example of a modcode table that may be used to implement ACM according to various embodiments of the present invention.
  • FIG. 2B illustrates an example of an address/SNR table that may be used to implement ACM according to various embodiments of the present invention.
  • FIG. 3 is a simplified block diagram illustrating a DVB-S2 framing format that may be used to implement ACM according to various embodiments of the present invention.
  • FIG. 4 is a simplified block diagram illustrating a communications device configured according to various embodiments of the present invention.
  • FIG. 5 is a flowchart illustrating a packet encapsulation and transmission format according to various embodiments of the present invention.
  • FIG. 6 is a flowchart illustrating a flow control process for packet transmission according to various embodiments of the present invention.
  • FIG. 7 is a flowchart illustrating a flow control and packet encapsulation process according to various embodiments of the present invention.
  • FIG. 8 is a simplified block diagram illustrating a device including a queueing unit configured according to various embodiments of the present invention.
  • FIG. 9 is a simplified block diagram illustrating an alternative communications device including a queueing unit configured according to various embodiments of the present invention.
  • FIG. 10 is a flow diagram illustrating a queueing process according to various embodiments of the present invention.
  • FIG. 11 is a flowchart illustrating a flow control queueing process for packet transmission according to various embodiments of the present invention.
  • FIG. 12 is flowchart illustrating an alternative flow control queueing process for packet transmission according to various embodiments of the present invention.
  • FIG. 13 is a simplified block diagram illustrating a communications device configured to use a linked list according to various embodiments of the present invention.
  • FIG. 14 is a simplified block diagram illustrating an alternative communications device configured to use a linked list according to various embodiments of the present invention.
  • FIGS. 15A and 15B are block diagrams illustrating use of a linked list according to various embodiments of the present invention.
  • FIG. 16 is a flow diagram illustrating a flow control process using a linked list according to various embodiments of the present invention.
  • FIG. 17 is a flowchart illustrating an iteration through a linked list in which elements are linked according to various embodiments of the present invention.
  • FIG. 18 is a flowchart illustrating an alternative process for iteration through a linked list in which elements are linked according to various embodiments of the present invention.
  • FIG. 19 is a simplified block diagram illustrating a communications device configured to vary a reliability margin according to various embodiments of the present invention.
  • FIG. 20 is a linear representation of a number of variable signal quality ranges for use according to various embodiments of the present invention.
  • FIG. 21 is a flowchart illustrating a variable reliability margin configured according to various embodiments of the present invention.
  • FIG. 22 is a flowchart illustrating an alternative process for modifying a reliability margin configured according to various embodiments of the present invention.
  • various embodiments may omit, substitute, or add various procedures or components as appropriate.
  • the methods may be performed in an order different than that described, and that various steps may be added, omitted or combined.
  • features described with respect to certain embodiments may be combined in various other embodiments.
  • the following systems, methods, and software may be a component of a larger system, wherein other procedures may take precedence over or otherwise modify their application.
  • a number of steps may be required before, after, or concurrently with the following embodiments.
  • FIG. 1 is a block diagram illustrating an example satellite communications system 100 configured according to various embodiments of the invention. While a satellite communications system is used to illustrate various aspects of the invention, it is worth noting that certain principles set forth herein are applicable to a variety of other wireless systems, as well.
  • the satellite communications system 100 includes a network 120 , such as the Internet, interfaced with a gateway 115 that is configured to communicate with one or more subscriber terminals 130 , via a satellite 105 .
  • the network 120 may be any type of network and can include, for example, the Internet, an IP network, an intranet, a local- or wide-area network, a virtual private network, the Public Switched Telephone Network (“PSTN”), or any other type of network supporting data communication between devices described herein, in different embodiments.
  • a network 120 may include both wired and wireless connections, including optical links.
  • the network 120 may also transmit information about link conditions for one or more subscriber terminals to the gateway 115 .
  • the network may connect the gateway 115 with other gateways (not pictured), which are also in communication with the satellite 105 , and which may share information on link conditions and other network metrics.
  • the gateway 115 provides an interface between the network 120 and the subscriber terminal 130 .
  • the gateway 115 may be configured to receive data and information directed to one or more subscriber terminals 130 , and can format the data and information (e.g., using ACM) for delivery to the respective destination terminal 130 via the satellite 105 .
  • the gateway 115 may be configured to receive upstream signals from the satellite 105 (e.g., from one or more subscriber terminals) directed to a destination in the network 120 , and can format the received signals for transmission along the network 120 .
  • a device (not shown) connected to the network 120 may communicate with one or more subscriber terminals through the gateway 115 .
  • Data and information may be sent from a device in the network 120 to the gateway 115 .
  • the gateway 115 may format a Medium Access Control (MAC) frame in accordance with a physical layer definition for transmission to the satellite 105 .
  • MAC Medium Access Control
  • a variety of physical layer transmission modulation and coding techniques may be used with certain embodiments of the invention, including those defined with the DVB-S2 and WiMAX standards.
  • the gateway 115 utilizes ACM in conjunction with one or more of the novel traffic control and shaping techniques described herein to direct traffic to the individual terminals.
  • the gateway 115 may use a broadcast signal, with a modulation and coding (“modcode”) format adapted for each packet to the link conditions of the terminal 130 or set of terminals 130 to which the packet is directed (e.g., to account for the variable service link 150 conditions from the satellite 105 to each respective terminal 130 ).
  • modcode modulation and coding
  • the gateway 115 may use an antenna 110 to transmit the signals to the satellite 105 .
  • the antenna 110 comprises a parabolic reflector with high directivity in the direction of the satellite and low directivity in other directions.
  • the antenna 110 may be implemented in a variety of alternative configurations.
  • the downstream signals may include, for example, a number of single carrier signals. Each signal carrier signal may be divided (e.g., using TDMA) into a number of virtual channels. The virtual channels may be the same size, or different sizes. In other embodiments, other channelization schemes may be used, such as Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Code Division Multiple Access (CDMA), or any number of hybrid or other schemes known in the art.
  • FDMA Frequency Division Multiple Access
  • OFDMA Orthogonal Frequency Division Multiple Access
  • CDMA Code Division Multiple Access
  • a geostationary satellite 105 is configured to receive the signals from the location of antenna 110 and within the frequency band and specific polarization transmitted.
  • the satellite 105 may process the signals received from the gateway 115 and forward the signal from the gateway 115 containing the MAC frame to one or more subscriber terminals 130 .
  • the satellite 105 operates in a multi-beam mode, transmitting a number of narrow beams each directed at a different region of the earth, allowing for frequency re-use.
  • This satellite 105 is configured as a “bent pipe” satellite, wherein the satellite may frequency convert the received carrier signals before retransmitting these signals to their destination, but otherwise perform little or no other processing on the contents of the signals.
  • a variety of physical layer transmission modulation and coding techniques may be used by the satellite 105 in accordance with certain embodiments of the invention, including those defined with the DVB-S2 and WiMAX standards.
  • a number of configurations are possible (e.g., using LEO satellites, or using a mesh network instead of a star network), as evident to those skilled in the art.
  • the service signals 150 transmitted from the satellite 105 may be received by one or more subscriber terminals 130 , via the respective subscriber antenna 125 .
  • the subscriber terminals 130 may receive the signals from the satellite 105 under very diverse link conditions.
  • the antenna 125 and terminal 130 together comprise a very small aperture terminal (VSAT).
  • VSAT very small aperture terminal
  • a variety of other types of antennas 125 may be used at the subscriber terminal 130 to receive a signal.
  • Each of the subscriber terminals 130 may comprise a single user terminal or, alternatively, a hub or router (not pictured) that is coupled to multiple user terminals.
  • Each subscriber terminal 130 may be connected to consumer premises equipment (CPE) 160 comprising, for example computers, local area networks, Internet appliances, wireless networks, etc.
  • CPE consumer premises equipment
  • a Multi-Frequency Time-Division Multiple Access (MF-TDMA) scheme is used for upstream links 140 , 145 , allowing efficient streaming of traffic while maintaining flexibility in allocating capacity among each of the subscriber terminals 130 .
  • MF-TDMA Multi-Frequency Time-Division Multiple Access
  • a number of frequency channels are allocated which may be fixed, or which may be allocated in a more dynamic fashion.
  • a Time Division Multiple Access (TDMA) scheme is also employed in each frequency channel. In this scheme, each frequency channel may be divided into several timeslots that can be assigned to a connection (i.e., a subscriber terminal 130 ).
  • one or more of the upstream links 140 , 145 may be configured with other schemes, such as FDMA, OFDMA, CDMA, or any number of hybrid or other schemes known in the art.
  • a subscriber terminal 130 may transmit information related to signal quality to the gateway 115 via the satellite 105 .
  • the signal quality may be a measured signal to noise ratio, an estimated signal to noise ratio, a bit error rate, a received power level, or any other communication link quality indicator.
  • the subscriber terminal itself may measure or estimate the signal quality, or it may pass information measured or estimated by other devices.
  • a subscriber terminal may also transmit data and information to a network 120 destination via the satellite 105 and gateway 115 .
  • the subscriber terminal 130 transmits the signals via the upstream uplink 145 to the satellite 105 using the antenna 125 .
  • a subscriber terminal 130 may transmit the signals according to a variety of physical layer transmission modulation and coding techniques, including those defined with the DVB-S2 and WiMAX standards. In various embodiments, the physical layer techniques may be the same for each of the links 135 , 140 , 145 , 150 , or may be different.
  • modcode table 200 is illustrated in the form of a block diagram.
  • This form of modcode table 200 may, for example, be used by a gateway 115 to determine the modcode to be used for packets destined for a subscriber terminal operating in a given signal quality range.
  • the table contains a column listing a number of modcode formats 205 .
  • Each modcode format 205 corresponds to a specified signal quality range 210 .
  • a signal quality range 210 encompassing the link may be identified, and the appropriate modcode may be selected. For example, if a destination link has a signal quality within Range 7, the modcode QPSK 3/4 may be used.
  • one or more of the ranges may include a reliability margin (which may be beneficial when channel conditions are changing rapidly, for example).
  • One or more of the ranges may be modified dynamically to adjust this reliability margin as well.
  • signal quality indicators may be used, such as a measured signal to noise ratio, an estimated signal to noise ratio, a bit error rate, a received power level, or any other communication link quality indicator. It is also worth noting that a number of other data structures may also be used to relate signal quality ranges to modcodes. In one embodiment, each signal quality is associated with a different packet forwarding queue. In still other embodiments, other information density parameters in addition to modcode changes may be added to further adapt a signal to environmental or other conditions.
  • FIG. 2B an example of an address/SNR table 250 is illustrated in the form of a block diagram.
  • This form of address/SNR table 250 may, for example, be used by a gateway 115 to lookup the signal quality 260 of a subscriber terminal 130 to which a packet is destined, based on the destination address 255 .
  • the tables in FIGS. 2A and 2B may be embodied on one or more memories, which may be either on or off chip, and may be used in conjunction with one another to correlate a MAC address with a particular modcode format.
  • destination MAC address is used in this example, other mechanisms may be used to identify particular subscriber terminals, including destination VLAN-1D, a Destination Internet Protocol (“DIP”) address, a private addressing ID, any other set of data comprising or otherwise correlated with a destination address.
  • the data address may be parsed from a received data packet after arrival at a device, or it may be received in any other manner known in the art. It is also worth noting that a number of other data structures may also be used to relate an address to signal quality.
  • ACM may then be encapsulated, coded, mapped and transmitted in a variety of ways, as known in the art.
  • One way to implement ACM is via the DVB-S2 standard, which specifically provides for its use.
  • ACM may change the modulation format and Forward Error Correction (FEC) codes (“modcodes”) to best match the current link conditions. This adaptation may occur on a frame by frame basis.
  • FEC Forward Error Correction
  • each frame is broadcast to all terminals 130 , but is only directed at a select subscriber terminal 130 (or small groups of terminals 130 ).
  • the waveform may be a single carrier waveform transmitted downstream from a gateway 115 to a subscriber terminal 130 in the system 100 of FIG. 1 .
  • the DVB-S2 system is used as an example, the principles specified herein are applicable to a range of systems.
  • a base-band frame 320 is made up of a base-band header 305 , a data field 310 , and padding 315 .
  • Data in the data field may include one or more IP packets encapsulated in a MAC frame, or may include other types of data as well.
  • the data field may include addressing information (e.g., IP address, MAC address, etc.) indicating the terminal or terminals to which the packet will be directed.
  • IP packets associated with different modcodes may be transmitted in the same base-band frame 320 , according to the lower order modcode.
  • the DVB-S2 specification provides that certain frames will be of fixed size regardless of the modcode used (i.e., a normal FEC frame is 64,800 bits, and a shortened FEC frame is 16,200 bits). Therefore, instead of simply padding a frame when there is additional space available and no other remaining packets associated with a current modcode, a data packet (or fragment thereof) associated with a higher order modcode may be inserted into the base-band frame. In one embodiment, the available space is filled with as many additional data packets as will fit without overflow.
  • Interleaving and FEC encoding may then be performed on the base-band frame 320 to produce an encoded base-band frame 325 , and outer coding parity bits 330 and inner coding parity bits 335 are appended to produce a FEC Frame 340 .
  • FEC frame 340 will be of fixed size, in other embodiments, the FEC frame 340 size may vary according to the modcode selected for the frame, to thereby produce, for example, frames of uniform duration in time.
  • the FEC frame 340 is bit mapped to the applicable constellation (e.g., QPSK, 8PSK, 16APSK, 32APSK), to produce a XFEC frame 345 made up of symbols representative of the frame contents.
  • a PL header 350 is added to the XFEC frame 345 , together forming the PL frame 365 .
  • the PL header 350 is made up of a start of frame (SOF) slot 355 of 26 symbols, and a modcode (MODCOD) slot 360 of 64 symbols specifying the modcode and size (i.e., whether normal or shortened FEC frame).
  • SOF start of frame
  • MODCOD modcode
  • the PL header 350 is encoded.
  • the PL frame 365 is then baseband shaped and quadrature modulated, as well as amplified and upconverted to be transmitted downstream.
  • FIG. 4 a simplified block diagram illustrates an example of a device 400 configured according to various embodiments of the invention.
  • the device 400 is the gateway 115 of FIG. 1 , transmitting packets downstream with modcodes adapted to the link to which the packets are directed.
  • the device 400 may be used in any number of different ACM implementations.
  • the device 400 in this embodiment includes a sorting unit 405 and a transmitting unit 410 .
  • the transmitting unit 410 is made up of an encapsulation unit 415 , a modulation and coding unit 420 , and a transmitter 425 .
  • These components may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits.
  • ASICs Application Specific Integrated Circuits
  • the device 400 may include different types and configurations of memory (not shown), which may be integrated into the hardware or may be one or more separate components.
  • the device 400 is a gateway 115 within the system 100 of FIG. 1 .
  • the system 100 is implemented in a star configuration where each terminal 130 communicates with the device 400 , receiving a wide band broadcast signal and searching the waveform for data destined for that terminal 130 .
  • Each terminal 130 estimates the SNR of the received signal, although in other embodiments, different signal quality metrics may be used. This information is included in the return path, which may be established via a satellite link or some other means. In other embodiments, the device 400 may receive the link signal quality data from other sources as well.
  • the device 400 then has an SNR estimate for each terminal (e.g., the address/SNR table 250 of FIG. 2B ), and may organize this data on one or more memories, which may be implemented in hardware, in a separate computer readable medium, or external to the device 400 .
  • a data packet may travel through a Class of Service/Quality of Service router (not shown), which may append several fields of information data packet. These fields may include the MAC address of the destination terminal, a counter field, and a time stamp field. Any of this functionality may be integrated into the device, as well.
  • the sorting unit 405 is configured to dynamically assign a different modcode to each data packet after each packet is received by the device. This assignment is based at least in part on a signal quality of a link to which the respective packet is destined.
  • the sorting unit 405 is configured to use the MAC address, in conjunction with the SNR estimate, to identify a modcode to use to communicate with a terminal 130 . To do so, the sorting unit 405 may produce or otherwise access a modcode table 200 , or other mechanism which correlates certain SNR estimate ranges with different modcodes.
  • a transmitting unit 410 is configured to transmit the sorted packets according to a defined order of progression, and to produce a broadcast signal output 430 .
  • the defined order of progression comprises transmitting each received data packet associated with a first modcode (perhaps in sequence from oldest to youngest), before incrementing to a next higher order modcode and transmitting each received data packet associated with a next higher order modcode (perhaps in sequence from oldest to youngest), and incrementing accordingly to the highest order modcode. The process is then repeated beginning from the lowest order modcode.
  • the term “defined order of progression” may include any packet forwarding selection or flow control algorithm known in the art.
  • a defined order of progression may encompass any of the number of queueing schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc.
  • the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and an out of order packet exceeding a threshold age is identified.
  • the interrupt timer interval in one embodiment is 10 mS, but a variety of other intervals are possible. For each 10 mS time interval, several frames may be built, and the real time required to transmit these frames will be tracked. This may be accomplished by totaling the number of symbols required to transmit the physical layer frames. Once enough frames have been created such that more than 10 mS of time is required to transmit them, the timer expires. A number of other timer calculations are possible, as evident to those skilled in the art.
  • the identified packet is the oldest received packet not yet transmitted (i.e., the threshold age is the age of the second oldest packet).
  • the identified packet is then transmitted, and the defined order of progression may be restarted from the oldest packet.
  • all packets above a second threshold age are sent before the order of progression is restarted.
  • the device 400 may control other flow modifications when the identified oldest packet is above certain threshold ages. For example, if the identified packet exceeds a first threshold age (e.g., 50 mS), the sorting unit 405 may be further configured to allow data packets associated with a threshold quality or class of service to enter, while blocking others. If the identified packet exceeds a second threshold age (e.g., 80 mS), the sorting unit 405 may be further configured to block all incoming packets until another period of the timer expires. In another embodiment, the transmitting unit 410 is further configured to vary the period of the timer based at least in part on changes in the age of the identified oldest packet (e.g., decreasing the period of the timer if the age of the oldest packet increases). While these changes may be associated with the age of the oldest identified packet (e.g., measured by the difference between timestamp and transmission), other latency and traffic flow measurements may be used to modify these parameters.
  • a first threshold age e.g., 50 mS
  • the sorting unit 405 is configured to vary a signal quality range associated with one or more modcodes to modify a reliability margin data for packets destined for a link within the varied signal quality range.
  • the sorting unit may be configured to increase the reliability margin when traffic is light, and decrease the reliability margin when traffic is heavy. This adjustment may, for example, be made based on the age of the oldest packet identified at the expiration of the timer (e.g., if T0>60 mS, set margin to 1 dB; if 60 mS>T ⁇ 40 mS, set margin to 2 dB; if 40 mS>T0, set margin to 3 dB).
  • the defined order of progression may include having the sorting unit 405 configured to group data packets associated with different modcodes for encapsulation in one frame to be transmitted according to a lowest order modcode of the different modcodes, the grouping to occur when there are no other remaining data packets that are associated with the lowest order modcode. For example, when there is additional space available in a base-band frame 320 and no other remaining packets are associated with a current modcode, a data packet (or fragment thereof) associated with a next higher order modcode may be inserted into the base-band frame 320 .
  • a higher order packet may be fragmented, for example, into a first fragment and a second fragment.
  • the first fragment may be sized to fill the available space, and transmitted in the first frame according to the lower order modcode.
  • the second fragment may then be transmitted in a following frame according to the higher modcode.
  • the transmitting unit 410 may include an encapsulation unit 415 .
  • the encapsulation unit 415 may be configured to encapsulate in a frame (e.g., a single base-band frame 320 ) one or more packets associated with a lower order modcode and one or more additional packets associated with a higher order modcode.
  • the transmitting unit 410 also includes a modulation and coding unit 420 configured to encode and map the frame according to the lower order modcode (e.g., to produce XFEC frame 345 ).
  • a transmitter 425 may baseband shape and quadrature modulate the frame, as well as amplify and upconvert the signal, to produce a broadcast signal output 430 .
  • FIG. 5 is a flowchart illustrating a process 500 of implementing adaptive coding and modulation in a broadcast signal. The process may be performed, for example, in whole or in part by the device 400 of FIG. 4 .
  • a first modcode is associated with a first signal quality range.
  • a higher order second modcode is associated with a second signal quality range of better quality.
  • a first data packet destined for a first link within the first signal quality range and a second data packet destined for a second link within the second signal quality range arc received.
  • the first data packet and at least a part of the second data packet are encapsulated in a single frame.
  • the first frame is transmitted in the broadcast signal according to the first modcode.
  • FIG. 6 is a flowchart illustrating a process 600 for controlling the flow of data traffic in a broadcast signal implementing adaptive coding and modulation. The process may be performed, for example, in whole or in part by the device 400 of FIG. 4 .
  • a modcode is dynamically assigned to each of a number of data packets based on a signal quality of a link to which each respective packet is destined.
  • each data packet is associated with a timestamp.
  • some of the received data packets are transmitted according to a defined order of progression.
  • the defined order of progression is interrupted upon expiration of a timer, and an out of order packet is transmitted with a timestamp exceeding a threshold age.
  • FIG. 7 is a flowchart illustrating a process 700 for controlling the flow of data traffic in a broadcast signal implementing adaptive coding and modulation. The process may be performed, for example, in whole or in part by the device 400 of FIG. 4 .
  • various modcodes are each associated with different signal quality ranges, the signal quality ranges including a reliability margin.
  • a modcode is assigned to each of a number of data packets based on a signal quality of a link to which each respective packet is destined.
  • a timestamp is associated with each of the data packets.
  • some of the data packets are transmitted according to a defined order of progression, the order providing for data packets assigned to different modcodes to be transmitted in a single frame according to the lower order modcode.
  • the defined order of progression is interrupted to transmit an oldest packet.
  • the defined order of progression is restarted from the oldest packet.
  • a measure of latency associated with the transmission is determined (e.g., based on the age of the transmitted oldest packet, or using other latency or flow characteristics).
  • at least one of the signal quality ranges associated with the modcodes are varied to modify the reliability margin, the varying based at least in part on the latency measure.
  • the period of the timer is varied based at least in part on the latency measure.
  • only packets with certain class or quality of service characteristics are allowed, while others are blocked, based at least in part on the characteristics of the oldest packet. The process may then be restarted from block 710 .
  • FIG. 8 a simplified block diagram illustrates an example of a queueing device 800 configured to queue and transmit packets according to their modcode.
  • the queueing device 800 may be the device 400 described in relation to FIG. 4 , implementing adaptive modulation and coding utilizing the queueing process described below.
  • the device 800 in this embodiment includes a queueing unit 805 , a number of packet forwarding queues 810 , and a transmitting unit 815 .
  • These components may be in communication with one another, and may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits.
  • ASICs Application Specific Integrated Circuits
  • Integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art.
  • FPGAs Field Programmable Gate Arrays
  • Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors.
  • the queues 810 may be embodied on one or more memories, which may be either on or off chip.
  • the device 800 is a gateway 115 within the system 100 of FIG. 1 .
  • the device 800 may be used in any number of different ACM implementations.
  • the system 100 is implemented in a star configuration where each terminal 130 communicates with the device 800 , receiving a wide band broadcast signal and searching the waveform for data destined for that terminal 130 .
  • Each terminal 130 may estimate the signal quality of the service link using any one of a variety of metrics, and transmit the estimate to the queueing device via the return path.
  • the device 800 may receive the link signal quality data from other sources as well.
  • the device 800 then has a receive signal estimate for each terminal (e.g., the address/SNR table 250 of FIG. 2B ), and may organize this data on one or more memories, which may be implemented in hardware, in a separate computer readable medium, or external to the device 800 .
  • a data packet from a data source may be received by the queueing device 800 .
  • the queueing device 800 includes a number of individual packet forwarding queues 810 , each assigned a different modcode and associated with a select one of a number of signal quality ranges.
  • each respective packet is received by a queueing unit 805 configured to place the packet into a select one of the packet forwarding queues 810 .
  • the particular queue selected is based on its association with a signal quality range encompassing a signal quality of a link to which the respective packet is destined. To make this assignment, the queueing unit 805 may produce or otherwise access a modcode table 200 , or other mechanisms which correlate certain signal quality estimate ranges with different modcodes.
  • the queueing unit 805 By queueing packets as they arrive, the queueing unit 805 is able to order the packets in the queues 810 from oldest to youngest. Thus, the queues 810 may be FIFO buffers, so the packets in each queue are in time order. (It is worth noting that in some embodiments, the sorting unit 405 of FIG. 4 may be implemented as the queueing unit 805 of FIG. 8 ).
  • a transmitting unit 815 directly or indirectly connected with the packet forwarding queues 810 , is configured to transmit the packets according to a defined order of progression, and to produce a broadcast signal output 820 .
  • the defined order of progression comprises transmitting each received data packet in a given forwarding queue associated with a first modcode (e.g., in sequence from oldest to youngest), before incrementing to the queue 810 associated with the next higher order modcode and transmitting each received data packet associated with a next higher order modcode (again, perhaps in sequence from oldest to youngest), and incrementing accordingly to the queue 810 with the highest order modcode.
  • the defined order of progression may provide for transmitting at least one data packet from a first selected queue and a data packet or fragment from a second selected queue in a single frame according to lower order modcode. For example, when there is additional space available in a base-band frame 320 and no other remaining packets are associated with a current modcode, a data packet (or fragment thereof) associated with a next higher order modcode may be inserted into the base-band frame 320 .
  • the term “defined order of progression” may include any of a number of queueing schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc.
  • the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and a packet exceeding a threshold age and from an out of order queue 810 is identified.
  • the identified packet is the oldest received packet not yet transmitted (i.e., the threshold age is the second oldest packet).
  • the identified packet is then transmitted, and the defined order of progression may be restarted from the transmitted packet.
  • the defined order of progression may provide for transmitting at least one data packet from the first selected queue and the data packet from the second selected queue in a single frame according to the first modcode
  • a data packet may travel from the data source through a Class of Service/Quality of Service router 930 , which may append the class or quality of service information field and an address field identifying the destination terminal.
  • a data packet may be transmitted to the queueing device 805 .
  • the queueing unit 805 in this embodiment may include a timestamp 905 unit, a counter 910 , a filtering unit 915 , and a margin unit 920 .
  • the queueing device 800 may utilize these components to control certain flow modifications.
  • the timestamp 905 unit may be used to append or otherwise associate a timestamp to a packet when it is received by the device, or at other processing stages. The timestamp may, therefore, be used to determine the “age” of given packet.
  • the timestamp may be used by other components of the queueing device 800 to determine latency associated with a particular packet or packets at different stages of processing (i.e., latency from receipt at the device 800 to transmission, latency within the queuing unit, etc.).
  • the queueing unit 805 may make use of the timestamp in a number of ways. For example, consider an interruption of the defined order of progression to identify an out of order packet. If age (determined through use of the timestamp 905 unit) of the identified packet exceeds a first threshold age (e.g., 60 mS), the filtering unit 915 may be configured to allow data packets associated with a threshold quality or class of service to enter, while blocking others. If the identified packet exceeds a second threshold age (e.g., 90 mS), the filtering unit 915 may be further configured to block all incoming packets until another period of the timer expires.
  • a first threshold age e.g. 60 mS
  • the filtering unit 915 may be configured to allow data packets associated with a threshold quality or class of service to enter, while blocking others. If the identified packet exceeds a second threshold age (e.g., 90 mS), the filtering unit 915 may be further configured to block all incoming packets until another period of the timer
  • the queueing unit 805 includes a margin unit 920 configured to vary a signal quality range associated with one or more queues.
  • the margin unit 920 may vary the signal quality range of a queue to modify a reliability margin for data packets destined for a link within the varied signal quality range.
  • the margin unit 920 may be configured to increase the minimum signal quality of a range when traffic is light, and decrease the minimum signal quality of a range when traffic is heavy. This adjustment may, for example, be made based on the age of the packet identified at the expiration of the timer 925 .
  • the queueing unit utilizes a counter 910 to associate an order with the data packets, perhaps on a per destination address basis.
  • the transmitting unit 815 may be configured to hold transmission of a data packet when the packet is out of the order specified by the counter.
  • the defined order of progression is interrupted upon expiration of a timer, and a packet exceeding a threshold age, and from an out of order queue 810 , is identified.
  • the timer may be located on, or off the device.
  • an on-device timer 925 is located in the transmitting unit 815 .
  • the transmitting unit 815 may be configured to vary the period of the timer based at least in part on the latency measure or a data flow measure (e.g., decreasing the period of the timer if the age of packets and the data flow through the device 800 increase). While these changes may be associated with the age of the packet identified from the out of order queue, other latency and traffic flow measurements may be used to modify these parameters (e.g., filtering unit 915 parameters, margin unit 920 parameters, or period of the timer 925 ).
  • FIG. 10 a flow diagram illustrates an example decision flow 1000 for a device, such as the queueing device 800 of FIG. 8 or 9 .
  • a timer such as the timer 925 in the transmitting unit 820 of FIG. 9 .
  • the timer then restarts.
  • these tables are updated with revised SNR information from the terminals.
  • Incoming data packets are filtered at block 1006 according to blocking rules based on latency measurements, and these rules may, for example, be implemented by the filtering unit 915 .
  • allowed packets are placed into respective queues 810 , based on the destination terminal SNR and the signal ranges applicable to the queues 810 .
  • the queue 810 with the oldest packet, and the age of that packet, are identified at block 1010 .
  • These first blocks in FIG. 10 ( 1002 , 1004 , 1006 , 1008 , 1010 ) may be initiated together at on or about the same time.
  • the reliability margin calculations for each modcode queue 810 may then be revised, at block 1012 , based on the age of the oldest packet. Also, the blocking rules may be modified, at block 1014 , also based on the age of the oldest packet. These revisions will be implemented, at block 1016 , upon the expiration of the timer. In other embodiments, the period of the timer may be modified based on the age of the oldest packet, as well.
  • the oldest packet (or fragment thereof) is moved from the identified queue 810 to the payload portion of a frame, for example, a base-band frame 320 for the DVB-S2 system.
  • a determination is made as to whether the frame is completed (e.g., a determination that there is no available space left in the frame). If the frame is complete, the frame is encapsulated and forwarded to the modulation and coding unit at block 1022 , where it is encoded and mapped accordingly.
  • a determination is made whether the frame includes a beginning of a fragment.
  • block 1026 indicates that the next frame will begin with the remaining portion of the fragment to complete the packet (regardless of whether the timer expires in the interim).
  • block 1028 a determination is made whether the timer has expired. If yes, at block 1048 the process 1000 is restarted, back to block 1002 .
  • the frame may continue to be filled. Similarly, if the timer has not expired at block 1028 , a new frame may be constructed. In each case, a determination is made at block 1030 regarding whether the last packet from a current queue 810 has been sent. If packets remain in the current queue 810 , the process returns to block 1018 to move the oldest packet from the current queue 810 to fill (or begin) the frame. However, if it is determined that no packets remain in the current queue 810 , a frame may still be filled or constructed with a packet from a queue associated with a higher order queue.
  • a frame is eventually completed and forwarded to the modulation and coding unit at block 1022 , and packets associated with different modcodes are in a single frame, the lowest order modcode associated with the packets of the frame is used. It will be evident to those skilled in the art how the process described may empty queues 810 to construct and fill frames, incrementing to next higher order non-empty queues 810 as current queues 810 are emptied.
  • the frame is padded at block 1036 (e.g., with the padding 315 of a DVB-S 2 base-band frame 320 ).
  • the frame is encapsulated and forwarded to the modulation and coding unit at block 1038 , where it is encoded and mapped accordingly.
  • a determination is made whether the timer has expired. If yes, the process 1000 is restarted at block 1048 . If the timer has not expired, at block 1042 a determination is made whether all lower order queues are empty.
  • the process decrements, at block 1044 , to the lowest order non-empty queue 810 , and then returns to block 1018 to move the oldest packet from that queue 810 to begin the next frame, with the process repeating in the manner described above from block 1018 .
  • an all pad frame is built at block 1046 .
  • the process returns to block 1038 , where the all pad frame is encapsulated and forwarded to the modulation and coding unit, where it is encoded and mapped accordingly, and the process continues from there.
  • FIG. 11 is a flowchart illustrating a process 1100 for controlling the flow of data traffic implementing adaptive coding and modulation using packet forwarding queues.
  • the process may be performed, for example, in whole or in part by the device 800 of FIG. 8 or 9 .
  • a different modcode is assigned to each of a number of packet forwarding queues, each queue associated with a different signal quality range.
  • received data packets are each placed into selected queues, the selected queue associated with a signal quality range encompassing the signal quality of a link to which the respective packet is destined.
  • at least some of the data packets are transmitted according to a defined order of progression.
  • the defined order of progression is restarted upon expiration of a timer to identify, and transmit, an out of order packet exceeding a threshold age. In one set of embodiments, this identified packet is the oldest packet remaining in the queues.
  • FIG. 12 a flowchart is shown which illustrates an alternative process 1200 for controlling the flow of data traffic using packet forwarding queues to implement adaptive coding and modulation.
  • the process may be performed, for example, in whole or in part by the device 800 of FIG. 8 or 9 .
  • modcodes are each associated with a signal quality range, the signal quality range including a reliability margin.
  • the modcodes are each assigned to one of a number of packet forwarding queues, each queue thereby associated with a different signal quality range.
  • respective data packets are each placed into selected queues, the selected queue for each packet being the queue associated with a signal quality range encompassing the signal quality of a link to which the respective packet is destined.
  • data packets are transmitted according to a defined order of progression, the order including emptying a queue and incrementing to the next higher order modcode queue, wherein select data packets assigned to different modcodes are transmitted in a single frame according to the lower order modcode.
  • the defined order of progression is interrupted upon the expiration of a timer to identify and transmit the oldest packet in the queues, from an out of order queue. The defined order of progression is then restarted, at block 1230 , from the oldest packet and its queue.
  • a measure of latency associated with the oldest packet is determined.
  • at least one of the signal quality ranges associated with the modcodes are varied to modify the reliability margin, based at least in part on the latency measure.
  • the period of the timer is also varied, at block 1245 , based at least in part on the latency measure.
  • packets with certain class or quality of service characteristics are allowed to enter the queues while others are blocked, this filtering based at least in part on the characteristics of the oldest packet (e.g., via the latency measure).
  • FIGS. 8-12 illustrate a set of embodiments in which packet forwarding queues arc used to implement various aspects of the invention
  • certain principles set forth may be applied using a variety of alternative data structures.
  • FIG. 13 a simplified block diagram illustrates an example of a traffic shaping device 1300 configured to utilize a linked list data structure to shape and control data traffic according to modcode in an ACM system.
  • the traffic shaping device 1300 may be the device 400 described in relation to FIG. 4 , implementing adaptive modulation and coding utilizing a linked list in the manner described below.
  • the device 1300 in this embodiment includes a processing unit 1305 , buffers 1310 , a linked list 1315 , and a transmitting unit 1320 .
  • These components may be in communication with one another, and may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware.
  • ASICs Application Specific Integrated Circuits
  • the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits.
  • Integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art.
  • FPGAs Field Programmable Gate Arrays
  • Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors.
  • the buffers 1310 and linked list 1315 may be embodied on one or more memories, which may be either on or off chip.
  • each terminal 130 may measure the signal quality of the service link using any one of a variety metrics, and transmit the measurement to the traffic shaping device 1300 via the return path.
  • the device 1300 may receive the link signal quality data from other sources as well.
  • the traffic shaping device 1300 may then have a receive signal measurement from each terminal (e.g., the address/SNR table 250 of FIG. 2B ), and may organize this data on one or more memories, which may be implemented in hardware, in a separate computer readable medium, or external to the device 1300 .
  • a data packet may travel from a data source through a Class of Service/Quality of Service router (not shown), which may append several fields of information data packet. These fields may include the QoS/CoS information for the packet, address information of the destination terminal, a counter field, and a time stamp field. Any of this functionality may be integrated into the device 1300 , as well.
  • the processing unit 1305 may store received data packets (and any appended data) in the buffers 1310 .
  • the processing unit 1305 also inserts a new element associated with the buffered data packet in a linked list 1315 , which will be used to shape the traffic as it is transmitted from the device 1300 .
  • the sorting unit 405 of FIG. 4 is the processing unit 1305 of FIG. 13 .
  • the linked list may be structured in a variety of ways, as known in the art, and the following explanation illustrates only a subset of the implementations possible.
  • the linked list may be characterized as a data structure made up of a sequence of elements, each element containing one (or more) field for data, and also containing two pointers linking the element to the next and previous elements.
  • the data in each element is made up of a token or other pointer referencing the buffered data packet (and any appended data) which the element represents.
  • the token or other pointer may reference a table which includes certain portions of the information from the buffered packet and other sources.
  • the token or other pointer may directly or indirectly reference the modcode and address/SNR tables ( 200 , 250 ) in FIGS. 2A and 2B .
  • the one (or more) data field from an element may be associated with the buffered data packet (and any appended data) which the element represents.
  • the linked list 1315 may be characterized as a data structure made up of a sequence of elements, each element containing a field (or fields) for data, and also containing pointers linking the element to the next and previous elements.
  • the linked list is a circularly linked list, where the last element in the list is linked back to the first.
  • the “top” of the list will hereinafter be referred to as part of the list holding the element associated with the oldest packet remaining to be forwarded, while the “bottom” of the list will hereinafter be referred to as the part of the list holding the element associated with the newest packet remaining to be forwarded.
  • packet forwarding queues may be used to shape and control traffic
  • a different though related mechanism may be used in the following embodiments.
  • each of a number of modcodes is related to signal quality ranges (without also necessarily be related to physical queues).
  • This relation could be embodied on one or more memories, which may be either on or off chip.
  • This relation may, for example, be the table 200 of FIG. 2A .
  • signal qualities ranges may be related to modcodes.
  • there may more than one range related to each modcode and the ranges may be of any size.
  • the processing unit 1305 may store received data packets (and any appended data) in the buffers 1310 .
  • the processing unit 1305 also inserts a new element associated with the buffered data packet in the linked list 1315 .
  • the processing unit 1305 may then identify a signal quality range associated with a given modcode. Identified items in the list will be removed in some embodiments, so that the top of the list will identify the oldest packets to be transmitted, and the linked list will proceed to the bottom in chronological order.
  • the processing unit 1305 will then iterate through the linked list 1315 to identify elements associated with data packets destined for links within the identified signal quality range.
  • the processing unit 1305 may circle to the top of the linked list 1315 , and iterate through to identify elements associated with links within a second signal quality range assigned to the next higher order modcode. This process may be repeated to identify elements associated with packets for incrementing higher modcodes. Once the signal quality range associated with the highest order modcode is emptied, the process is then repeated beginning from the signal quality range associated with the lowest order modcode. This order of progression is merely one example of many, but will be used for much of the discussion below
  • the transmitting unit 1320 is configured to access or otherwise receive the buffered data packets.
  • the transmitting unit 1320 may transmit the packets in an order corresponding to a sequence in which their associated elements are identified, and according to the modcode assigned to the identified signal quality range.
  • the transmitting unit 410 of FIG. 4 is the transmitting unit 1320 of FIG. 13 .
  • the memory e.g., buffers 1310 for the transmitted packet may be allocated as available.
  • the processing unit 1305 may be configured to identify packets according to a defined order of progression. Also, the transmitting unit 1320 may be configured to transmit the packets according to the defined order of progression, and to produce a broadcast signal output 1325 .
  • the defined order of progression comprises identifying and transmitting received data packets in a given signal quality range associated with a first modcode (e.g., in sequence from oldest to youngest), before identifying and transmitting each received data packet associated with a next higher order modcode (again, perhaps in sequence from oldest to youngest), and incrementing accordingly to the highest order modcode. Once the packets associated with highest order modcode are identified, the process may then be repeated beginning from the identified packets from the lowest order modcode.
  • the defined order of progression may provide for transmitting at least one data packet within a first signal quality range assigned a first modcode and a data packet or fragment from a second signal quality range assigned a second modcode in a single frame according the lower order modcode. For example, when there is additional space available in a base-band frame 320 and no other remaining packets are associated with a current modcode, a data packet (or fragment thereof) associated with a next higher order modcode may be inserted into the base-band frame 320 .
  • the term “defined order of progression” includes any of a number of schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc.
  • the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and a packet exceeding a threshold age is identified.
  • the identified packet is the oldest received packet not yet transmitted (i.e., it is the packet from the top of the list). The identified packet is then transmitted, and the defined order of progression may be restarted from the transmitted packet (i.e., the “current” signal quality range will become the signal quality range of the identified packet, and the iteration through the list will continue).
  • the processing unit 805 in this embodiment may include a timestamp 1405 , a filtering unit 1410 , a margin unit 1415 , and a timer 1420 .
  • the traffic shaping device 1300 may utilize these components to control certain flow modifications.
  • the timestamp 1405 may be used to append or otherwise associate a time to a packet when it is received by the device, or at other processing stages. The timestamp 1405 may, therefore, be used to determine the “age” of the given packet.
  • the timestamp may be used by other components of the traffic shaping device 1300 to determine latency associated with a particular packet or packets at different stages of processing (i.e., latency from receipt at the device 1300 to transmission, latency within the processing unit 1305 , etc.).
  • the processing unit 1305 may make use of a timestamp in a number of ways. For example, consider an interruption of the defined order of progression to identify an out of order packet. If age (determined through use of the timestamp 1405 ) of the identified packet exceeds a first threshold age (e.g., 70 mS), the filtering unit 1410 may be configured to allow an element to be inserted into the linked list 1315 only if a data packet has a threshold quality or class of service, while blocking others. If the identified packet exceeds a second threshold age (e.g., 120 mS), the filtering unit 1410 may be further configured to prevent any elements from being inserted into the linked list. The processing unit 1305 may be configurable to change these thresholds.
  • a first threshold age e.g. 70 mS
  • the filtering unit 1410 may be configured to allow an element to be inserted into the linked list 1315 only if a data packet has a threshold quality or class of service, while blocking others.
  • a second threshold age e.
  • the processing unit 1305 includes a margin unit 1415 configured to dynamically change a signal quality range associated with one or more queues.
  • the margin unit 920 may vary the signal quality range associated with a modcode to modify a reliability margin for data packets destined for a link within the varied signal quality range.
  • the margin unit 1415 may be configured to increase the minimum signal quality of a range when traffic is light, and decrease the minimum signal quality of a range when traffic is heavy. This adjustment may, for example, be made based on the age of the packet identified at the expiration of the timer 1420 .
  • the defined order of progression is interrupted upon expiration of a timer, and a packet exceeding a threshold age, and from an out of order signal quality range, is identified.
  • the timer may be located on, or off the device.
  • an on-device timer 1420 is located in the processing unit 1305 .
  • the processing unit 1305 may be configured to change the period of the timer based at least in part on the latency measure or a data flow measure (e.g., decreasing the period of the timer if the age of the packets and data flow through the device 1300 increase). While these changes may be associated with the age of the packet identified, other latency and traffic flow measurements may be used to modify the parameters related to reliability margin, block and allow rules, and period of the timer.
  • linked list and buffers may be located in separate areas of memory, or share an area of memory 1425 .
  • FIG. 15A a block diagram 1500 illustrating a simplified example of an ACM implementation using a linked list is shown.
  • the block diagram illustrates how a linked list 1505 may be used to control the flow of traffic.
  • the linked list 1505 of FIG. 15 may be the linked list 1315 of FIGS. 13 and 14 .
  • the linked list 1505 is a data structure made up of a sequence of elements (or nodes), each element containing one (or more) fields for data, and also containing two pointers linking the element to the next and previous elements.
  • the pointers linking each element to the next and previous elements are shown as links 1515 . While the elements 1-25 in FIG.
  • the data in each element is made up of a token or other pointer referencing a buffered data packet (and any appended data) which the element represents.
  • the token or other pointer may indirectly reference a table which includes certain portions of the information from the buffered packet and other sources. For example, in this embodiment a table 1510 is indirectly connected to linked list 1505 , and the table 1510 shows the SNR estimate for the link associated with a variety of MAC addresses.
  • the linked list 1505 is a circularly linked list, where the last element in the list is linked back to the first.
  • the “top” of the list will be referred to as part of the list holding the element associated with the oldest packet remaining to be forwarded, while the “bottom” of the list will be referred to as the part of the list holding the element associated with the newest packet remaining to be forwarded.
  • their associated elements are inserted into the bottom of the list, to thereby construct the list.
  • packets are identified for transmission, their associated elements are removed from the list.
  • FIG. 15A illustrates the list at first time (T 1 ).
  • a first signal quality range includes SNR “a”, but no other SNRs are in the range.
  • the device 1300 may identify the MAC address of the element, and then access the table 1510 - a to determine if the element is associated with a MAC address in the range.
  • the device 1300 iterates through the linked list 1505 - a from elements 1-25, identifying and removing elements 1, 8, 17, and 24, because these elements are associated with SNRs within the range.
  • a second signal quality range associated with the next higher modcode includes SNR “g”, but no other SNRs are in the range.
  • the device 1300 may identify the MAC address of the element, and then access the table 1510 - a to determine if the element is associated with a MAC address in the range.
  • the device 1300 iterates through the linked list 1505 , identifying and removing elements 3 and 19, because these elements are associated with SNRs within the second range.
  • the packets associated with elements 1, 8, and 17 are transmitted in a first frame according to the modcode assigned to the first signal quality range. However, because there is space in the DVB-S2 base-band frame 320 , packets associated with elements 24 and 3 are transmitted in a second frame according to the modcode assigned to the first signal quality range.
  • the packet associated with element 19 are transmitted in a third frame according to the modcode assigned to the second signal quality range.
  • FIG. 15B shows the linked list 1505 - b at a second time (T 2 ) after the device has iterated through elements 1-25, then through 2-7, 9-16, and 18-23, at which time the timer expires.
  • T 2 a second time
  • elements 1, 3, 8, 17, 19, and 24 have been removed from the linked list 1505 - b
  • new elements 26-28 have been added, and the elements that remain are linked from oldest at the top to newest at the bottom.
  • the device 1300 instead of iterating though elements 25-28, the device 1300 will go to the top of the linked list to identify the oldest element (element 2) because of the expiration of the timer.
  • the device will identify the signal quality range of this identified element, and iterate from element 2 down through the list, identifying other elements associated with packets in this range. Also note that with the expiration of the timer, the table 1510 - b is updated, and there is a new SNR for MAC address 4.
  • the foregoing example is used only to illustrate a simplified example of how a linked list may be used in various embodiments of the invention.
  • FIG. 16 a flow diagram illustrates an example decision flow 1600 for a device, such as the traffic shaping device 1300 of FIG. 13 or 14 .
  • a linked list such as the linked list 1505 of FIGS. 15A or 15 B, is ordered chronologically with the oldest elements at the top of the list.
  • a timer such as the timer 1420 in the processing unit 1305 of FIG. 1400 .
  • the timer then restarts.
  • different SNR ranges are associated with different modcodes.
  • these tables are updated with revised SNR information from the terminals.
  • Incoming data packets are filtered at block 1606 according to blocking rules based on latency measurement for the device 1300 , and these rules may for example be implemented by the filtering unit 1410 .
  • allowed packets are associated with elements, and the elements are inserted into the bottom of the linked list.
  • the signal quality range encompassing the signal quality for the link of the data packet associated with the element at the top of the list is identified.
  • the reliability margin calculations for each modcode may then be revised, at block 1612 , based on the age of the packet at the top of the list (e.g., by varying the signal quality range associated with the modcode).
  • the blocking rules may be modified at block 1614 , also based on the age of the packet at the top of the list (i.e., the oldest packet).
  • These revisions will be implemented at block 1616 , upon the expiration of the timer.
  • the period of the timer may be modified based on the age of the oldest packet, as well. Note, also, that in other embodiments, other latency or flow measurements may be used to adjust the reliability margin, filtering rules, or period of the timer.
  • the packet (or fragment thereof) associated with the element from the top of the list is moved from the buffer to the payload portion of a frame, for example, a base-band frame 320 for the DVB-S2 system.
  • the element may then be removed from the top of the list.
  • a determination is made as to whether the frame is completed (e.g., a determination that there is no available space left in the frame). If the frame is complete, the frame is encapsulated and forwarded to the modulation and coding unit at block 1622 , where it is encoded and mapped accordingly.
  • a determination is made whether the frame includes a beginning of a fragment.
  • block 1626 indicates that the next frame will begin with the remaining portion of the fragment to complete the packet (regardless of whether timer expires in interim).
  • block 1628 a determination is made whether the timer has expired. If yes, at block 1650 the process 1600 is restarted, back to block 1602 .
  • the frame may continue to be filled. Similarly, if the timer has not expired at block 1628 , a new frame may be constructed. In each case, a determination is made at block 1630 regarding whether the last packet from the current signal quality range has been sent. This is accomplished by iterating down through the elements of the linked list and checking whether the SNRs of each associated data packet fall with the current range. If so, the next applicable element down the list is identified at block 1632 , and the process returns to block 1618 to move the packet associated with the element from the buffers to fill (or begin) the frame. However, if it is determined that no packets remain in the current signal quality range (i.e., the bottom of the linked list is reached), a frame may still be filled or constructed with a packet from a queue associated with a higher order queue.
  • the lowest order modcode associated with the packets of the frame is used. It will be evident to those skilled in the art how the process described may identify the packets from a signal quality range assigned to a modcode to construct and fill frames, and then circle to the top of a list to identify packets from the signal quality range associated with the next higher modcode.
  • the frame is padded at block 1638 (e.g., with the padding 315 of a DVB-S2 base-band frame 320 ).
  • the frame is encapsulated and forwarded to the modulation and coding unit at block 1640 , where it is encoded and mapped accordingly.
  • a determination is made whether the timer has expired. If yes, the process 1600 is restarted at block 1650 . If the timer has not expired, at block 1644 , a determination is made whether any elements associated with packets assigned to lower order modcodes remain in the linked list.
  • an all pad frame is built at block 1648 .
  • the process returns to block 1640 , where the all pad frame is encapsulated and forwarded to the modulation and coding unit, where it is encoded and mapped accordingly, and the process continues from there.
  • FIG. 17 is a flowchart illustrating a process 1700 for controlling the flow of data traffic by implementing adaptive coding and modulation using a linked list data structure. The process may be performed, for example, in whole or in part, by the device 1300 of FIG. 13 or 14 .
  • each of a number of data packets is associated with a signal quality, the signal quality being a representative signal quality of a link to which the packet is destined.
  • a different modcode is assigned to each of a number of signal quality ranges.
  • a number of elements are inserted into a linked list, each element associated with one of the data packets.
  • the linked list is iterated through to identify elements associated with links within a first signal quality range.
  • data packets are transmitted in an order corresponding to a sequence in which their associated elements are identified, the transmission according to a first modcode assigned to the first signal quality range.
  • FIG. 18 a flowchart is shown which illustrates an alternative process 1200 for controlling the flow of data traffic using linked list data structures to implement adaptive coding and modulation.
  • the process may be performed, for example, in whole or in part, by the device 1300 of FIG. 13 or 14 .
  • different modcodes are assigned to each of a number of signal quality ranges.
  • a number of data packets are associated with a signal quality, the signal quality being a representative signal quality of a link to which each packet is destined.
  • a number of elements each associated with one of the data packets are inserted.
  • the linked list is iterated through to identify elements associated with links within a first signal quality range.
  • the linked list is iterated through to identify elements associated with links within a second, next higher signal quality range.
  • data packets are transmitted in an order corresponding to a sequence in which their associated elements are identified, wherein one or more frames are transmitted according to a first modcode assigned to the first signal quality range, and each frame includes a packet from both ranges.
  • a pointer circles to the top of list to thereby identify the oldest packet in the linked list.
  • the packet may then be transmitted.
  • a measure of latency associated with the oldest packet is determined.
  • at least one of the signal quality ranges associated with the modcodes is changed to modify a reliability margin, based at least in part on the latency measure.
  • the period of the timer is modified based at least in part on the latency measure.
  • only elements associated with packets with certain class or quality of service characteristics are allowed to enter the linked list, while others are blocked, based at least in part on the characteristics of the latency measure.
  • FIG. 19 a simplified block diagram illustrates an example of a flow control and traffic shaping device 1900 configured to dynamically change the reliability margins associated with different modcodes in an ACM system.
  • the flow control and traffic shaping device 1900 may be the device 400 described in relation to FIG. 4 , implementing adaptive modulation and coding utilizing a dynamically variable reliability margin.
  • the device 1900 in this embodiment includes a processing unit 1905 , a transmitting unit 1910 , and a table 200 in which modcodes are assigned to various signal quality ranges.
  • These components may be in communication with one another, and may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits.
  • ASICs Application Specific Integrated Circuits
  • Integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art.
  • FPGAs Field Programmable Gate Arrays
  • Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors.
  • the modcode/signal quality range table 200 may be embodied on one or more memories, which may be either on or off chip.
  • each terminal 130 may measure the signal quality of the service link using any one of a variety of metrics, and transmit the measurement to the flow control and traffic shaping device 1900 via the return path.
  • the device 1900 may receive the link signal quality data from other sources as well. The device 1900 may then have receive signal quality metrics for each receiving terminal (e.g., the address/SNR table 250 of FIG. 2B ), and may organize this data on one or more memories.
  • the processing unit 1905 is configured to assign a different modcode to each data packet after the packet is received by the device. This assignment is based at least in part on a signal quality of a link to which the respective packet is destined.
  • the processing unit 1905 is configured to use a destination, in conjunction with the signal quality estimate, to identify a modcode to use to communicate with a terminal 130 . To do so, the processing unit 1905 accesses a modcode table 200 , or other mechanisms which correlate certain signal quality ranges with different modcodes.
  • the processing unit 1905 in this embodiment is configured to dynamically change a signal quality range associated with one or more modcodes.
  • the processing unit 1905 may change or otherwise vary the signal quality range associated with a modcode to modify a reliability margin for data packets destined for a link within that signal quality range.
  • the processing unit 1905 may be configured to increase the minimum signal quality of a particular range when traffic is light, and decrease the minimum signal quality of a particular range when traffic is heavy.
  • the processing unit 1905 in this embodiment may also possess the functionality of the margin units ( 920 , 1415 ) described in other embodiments.
  • the reliability margin 2005 for each of a number of modcodes is shown, as well.
  • the lower limit 2010 of the E s /N o value for a particular modcode is shown as the point Rn in FIG. 20 .
  • the lower limit 2010 is a somewhat arbitrary characterization, as it may be calculated in a number of different ways. For purposes of this discussion, it may include any identified, requisite, or otherwise suggested boundary for the lower limit for an E s /N o value of a particular modcode.
  • the implemented lower limit 2015 of an E s /N o value is shown as well, as points Mn in FIG. 20 , and is the lower limit 2010 plus a reliability margin for a particular modcode.
  • a reliability margin 2005 is, therefore, the difference between a lower limit 2010 and an implemented lower limit 2015 , and may include any environmental, weather, implementation, or other margin.
  • the reliability margin for one or more modcodes may be varied dynamically.
  • modcode2 2020 For purposes of example, modcode2 2020 .
  • the reliability margin 2015 may be increased (e.g., to 4 dB) without impacting latency or flow.
  • the reliability margin may be dynamically increased as traffic lightens.
  • the flow demands on the device 1900 may be increased.
  • the reliability margin 2015 may be dynamically decreased as traffic increases, either incrementally (e.g., 4 dB, to 3 dB, to 2 dB, to 1 dB, to 0.5 dB), or otherwise. A number of factors (latency, flow, anticipated traffic, etc.) may be used to dynamically control a reliability margin, as will be discussed in further detail below.
  • the reliability margin 2015 is zero.
  • the reliability margin is fixed, and the signal quality ranges may vary only with changes in weather or other environmental conditions.
  • the processing unit 1905 may perform other functions in addition to dynamically adjusting the signal quality range associated with different modcodes. For example, the processing unit 1905 may identify packets for transmission based on modified signal quality ranges, and according to a defined order of progression. The transmitting unit 1910 may transmit packets according to the defined order of progression, and produce a broadcast signal output 1915 .
  • the defined order of progression entails transmitting each received data packet in a given modified signal quality range assigned to a first modcode (e.g., in sequence from oldest to youngest), before incrementing to the next higher order modcode and transmitting each received data packet in a modified signal range associated with a next higher order modcode (again, perhaps in sequence from oldest to youngest), and incrementing accordingly to the highest order modcode.
  • the process is then repeated beginning from a modified signal quality range associated with the lowest order modcode.
  • the defined order of progression may provide for transmitting at least one data packet from a first modified signal quality range and a data packet or fragment from a second modified signal quality range according to the lower order modcode.
  • the term “defined order of progression” may include any of a number of packet forwarding schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc., or perhaps randomly.
  • the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and a packet exceeding a threshold age, and from an out of order signal quality range, is identified and transmitted.
  • the identified packet in one embodiment is the oldest received packet not yet transmitted (i.e., the threshold age is the second oldest packet).
  • the defined order of progression may be restarted from the transmitted packet.
  • the age of the out of order packet may be utilized in a variety of ways to modify the control of packets through the device 1900 .
  • other latency and flow measurements may be made by the processing unit 1905 and the transmitting unit 1910 .
  • the delay at the device 1900 associated with certain functions and components, or groups of functions and components, may be measured.
  • This type of latency measurement may occur for the out of order packet, or select groups of other packets.
  • the latency measurement may, for example, simply be a count of those packets transmitted that are over some threshold age.
  • a number of latency and packet flow measurements are known in art, and any may be used herein.
  • NOC network operations center
  • a NOC may transmit certain latency statistics or flow information to a device.
  • a NOC may also provide information on a future change in traffic flow.
  • a variety of network and testing tools are known in the art that may provide flow statistics, latency measurements, and other network information to a device 1900 .
  • the processing unit 1905 may use the latency information, flow statistics, and additional network information described above to dynamically change a signal quality range associated with a given modcode and thereby to modify the associated reliability margin.
  • the reliability margin may be adjusted based on the age of the identified out of order packet, for example: if T0>90 mS, set reliability margin to 0.5 dB; if 90 mS>T0 ⁇ 60 mS, set reliability margin to 1 dB; and if 60 mS>T0, set margin to 2 dB.
  • Other thresholds may be established to modify signal quality ranges (i.e., to change the reliability margin) based on the other latency information, flow statistics, and additional network information described above.
  • the processing unit 1305 may make use of the latency information, flow statistics, and additional network information described above in a number of other ways. It may use all the received information, or only selected aspects of the received information. By way of example, in addition to modifying the reliability margin, filtering rules for blocking or allowing certain packets may be changed to account for the latency information, flow statistics, and/or additional network information described above. For example, in periods of higher traffic, QoS/CoS priority filtering rules may be implemented. Also, the period of the timer may be modified based on the latency information, flow statistics, and/or additional network information described above. Thus, the period may be decreased when latency increases, to more regularly jump to the oldest remaining packets.
  • FIG. 21 is a flowchart illustrating a process 2100 for controlling the flow of data traffic by implementing adaptive coding and modulation using a dynamic reliability margin. The process may be performed, for example, in whole or in part, by the device 1900 of FIG. 19 .
  • a different modcode is assigned to each of a number signal quality ranges.
  • one or more of the signal quality ranges are dynamically varied to modify a reliability margin for delivery of data packets destined for a link with a signal quality within the range.
  • FIG. 22 is a flowchart illustrating an alternative process 2200 for controlling the flow of data traffic by dynamically modifying certain factors in an ACM system. The process may be performed, for example, in whole or in part by the device 1900 of FIG. 19 .
  • a different modcode is assigned to each of a number of signal quality ranges.
  • data packets are transmitted in a defined order of progression, at least a subset is transmitted according to the modcode assigned to their destination link.
  • a timer expires, and an out of order packet exceeding a threshold age is identified at block 2220 , thereby interrupting the defined order of progression.
  • transmission of data packets is restarted in a defined order of progression from the identified out of order packet.
  • a range of latency and flow measurements may be made or received at block 2245 .
  • the age of the out of order packet may be determined at block 2230 , while in other embodiments, other latency measurements associated with the packet may be made as well.
  • other latency factors attributed to a flow or the device 1900 may be measured, and additional flow statistics may be compiled or analyzed.
  • network data may be received at block 2240 .
  • This range of latency and flow measurements 2245 may be used, in whole or in part, to calculate a modification to one or more parameters from a group of traffic shaping and flow control parameters 2265 .
  • the reliability margin attributable to one or more modcodes may be changed in light of the latency and flow measurements 2245 .
  • the period for the timer may be changed in light of the latency and flow measurements 2245 .
  • the filtering rules related to blocking or selective blocking based on QoS/CoS may be changed in light of the latency and flow measurements 2245 .
  • the embodiments may be described as a process which is depicted as a flowchart or a flow diagram. Although they may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed, but could have additional steps not included in the figure.
  • the term “memory” may represent one or more devices or components thereof for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices or other machine readable mediums for storing information.
  • ROM read only memory
  • RAM random access memory
  • magnetic RAM magnetic RAM
  • core memory magnetic disk storage mediums
  • optical storage mediums flash memory devices or other machine readable mediums for storing information.
  • computer-readable medium includes, but is not limited to, portable or fixed storage devices, optical storage devices, wireless channels, a sim card, other smart cards, and various other mediums capable of storing, containing or carrying instructions or data.
  • embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof.
  • the program code or code segments to perform the necessary tasks may be stored in a machine readable medium such as a storage medium. Processors may perform the necessary tasks.

Abstract

A process is described to build physical layer frames with a modcode adapted to the signal quality of a destination terminal. Data packets assigned to the same modcode may be sent in the same frame, although packets associated with higher modcodes may be used to complete a frame before switching to the applicable higher modcode for construction of subsequent frames. After an interval, the order of progression is restarted with an out of order packet above a threshold age. Flow control filtering mechanisms and a variable reliability margin may be used to adapt dynamically to the current data traffic conditions.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application claims priority from co-pending U.S. Provisional Patent Application No. 60/731,122, filed Oct. 28, 2005, entitled “ADAPTIVE CODING AND MODULATION FOR BROADBAND DATA TRANSMISSION,” which is hereby incorporated by reference, as if set forth in full in this document, for all purposes.
  • This application is related to the following U.S. patent applications: U.S. Patent Application No. ______, Attorney Docket No. 026258-002320US, filed Oct. 30, 2006, entitled “ADAPTIVE CODING AND MODULATION QUEUING METHODS AND DEVICES”; U.S. Patent Application No. ______, Attorney Docket No. 026258-002330US, filed Oct. 30, 2006, entitled “ADAPTIVE CODING AND MODULATION USING LINKED LIST DATA STRUCTURES”; and U.S. Patent Application No. ______, Attorney Docket No. 026258-002340US, filed Oct. 30, 2006, entitled “ADAPTIVE CODING AND MODULATION FLOW CONTROL AND TRAFFIC SHAPING METHODS AND DEVICES”. This application hereby incorporates by reference herein the content of each of the aforementioned applications in their entirety and for all purposes.
  • FIELD OF THE INVENTION
  • The present invention relates to wireless communications in general and, in particular, to adaptive coding and modulation.
  • BACKGROUND OF THE INVENTION
  • Bi-directional wireless systems (such as satellite) may benefit from the use of adaptive coding and modulation (“ACM”). Using ACM, the modulation format and Forward Error Correction (“FEC”) codes for a signal may be adapted to better match the link conditions for each user in a multi-user system. A return channel or other means may be used to report the conditions of a receiving terminal. These link conditions are often characterized by the individual user's (or terminal's) signal to noise ratio (“SNR”). In a broadcast system, for example, the waveform broadcast to a number of users includes data packets designated only for an individual terminal (or small group of terminals). A message transmitted to a user requires fewer symbols (and thus less time) when a higher order modulation and higher code rate is used. Lower order modulation and lower code rate are more reliable but require more time to transmit the same size message. Using ACM, each packet may be transmitted at an optimized modulation and coding (“modcode”) level given the destination terminal's link conditions.
  • Wireless channels may suffer from time varying channel conditions. Signals traveling in changing environmental conditions may be scattered, reflected, and diffracted, causing varying channel conditions over time. These changes may, for example, be due to changing weather conditions or movement of objects. There is a need for new ways to shape and control ACM data traffic dynamically, so that the traffic may be more efficiently transmitted to select terminals.
  • BRIEF SUMMARY OF THE INVENTION
  • A process is described to build physical layer frames with a modcode adapted to the signal quality of a destination terminal. Data packets assigned to the same modcode are generally sent in the same frame, although packets associated with higher modcodes may be used to complete a frame before switching to the applicable higher modcode for construction of subsequent frames. After certain time intervals, an order of progression is restarted with an out of order packet above a threshold age. Flow control filtering mechanisms and a variable reliability margin may be used to adapt dynamically to the current data traffic conditions.
  • In one set of embodiments, packet forwarding queues are used to control the flow of packets according to modcode. Each queue is assigned to a different modcode, and is thereby associated with a signal quality range. Packets are placed into a queue associated with a signal quality range encompassing the link to which the packet is destined. In another set of embodiments, packets are associated with elements of a linked list. In such embodiments, the flow of packets is controlled by iterating through the linked list to identify packets within select signal quality ranges. Various device and system configurations are described to implement the processes set forth above, as well.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • A further understanding of the nature and advantages of the present invention may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
  • FIG. 1 illustrates a satellite communications system in which adaptive coding and modulation (“ACM”) may be implemented according to various embodiments of the present invention.
  • FIG. 2A illustrates an example of a modcode table that may be used to implement ACM according to various embodiments of the present invention.
  • FIG. 2B illustrates an example of an address/SNR table that may be used to implement ACM according to various embodiments of the present invention.
  • FIG. 3 is a simplified block diagram illustrating a DVB-S2 framing format that may be used to implement ACM according to various embodiments of the present invention.
  • FIG. 4 is a simplified block diagram illustrating a communications device configured according to various embodiments of the present invention.
  • FIG. 5 is a flowchart illustrating a packet encapsulation and transmission format according to various embodiments of the present invention.
  • FIG. 6 is a flowchart illustrating a flow control process for packet transmission according to various embodiments of the present invention.
  • FIG. 7 is a flowchart illustrating a flow control and packet encapsulation process according to various embodiments of the present invention.
  • FIG. 8 is a simplified block diagram illustrating a device including a queueing unit configured according to various embodiments of the present invention.
  • FIG. 9 is a simplified block diagram illustrating an alternative communications device including a queueing unit configured according to various embodiments of the present invention.
  • FIG. 10 is a flow diagram illustrating a queueing process according to various embodiments of the present invention.
  • FIG. 11 is a flowchart illustrating a flow control queueing process for packet transmission according to various embodiments of the present invention.
  • FIG. 12 is flowchart illustrating an alternative flow control queueing process for packet transmission according to various embodiments of the present invention.
  • FIG. 13 is a simplified block diagram illustrating a communications device configured to use a linked list according to various embodiments of the present invention.
  • FIG. 14 is a simplified block diagram illustrating an alternative communications device configured to use a linked list according to various embodiments of the present invention.
  • FIGS. 15A and 15B are block diagrams illustrating use of a linked list according to various embodiments of the present invention.
  • FIG. 16 is a flow diagram illustrating a flow control process using a linked list according to various embodiments of the present invention.
  • FIG. 17 is a flowchart illustrating an iteration through a linked list in which elements are linked according to various embodiments of the present invention.
  • FIG. 18 is a flowchart illustrating an alternative process for iteration through a linked list in which elements are linked according to various embodiments of the present invention.
  • FIG. 19 is a simplified block diagram illustrating a communications device configured to vary a reliability margin according to various embodiments of the present invention.
  • FIG. 20 is a linear representation of a number of variable signal quality ranges for use according to various embodiments of the present invention.
  • FIG. 21 is a flowchart illustrating a variable reliability margin configured according to various embodiments of the present invention.
  • FIG. 22 is a flowchart illustrating an alternative process for modifying a reliability margin configured according to various embodiments of the present invention.
  • DETAILED DESCRIPTION OF THE INVENTION
  • This description provides exemplary embodiments only, and is not intended to limit the scope, applicability or configuration of the invention. Rather, the ensuing description of the embodiments will provide those skilled in the art with an enabling description for implementing embodiments of the invention. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the appended claims. Different aspects and elements of the embodiments may be combined in a similar manner.
  • Thus, various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that in alternative embodiments, the methods may be performed in an order different than that described, and that various steps may be added, omitted or combined. Also, features described with respect to certain embodiments may be combined in various other embodiments. It should also be appreciated that the following systems, methods, and software may be a component of a larger system, wherein other procedures may take precedence over or otherwise modify their application. Also, a number of steps may be required before, after, or concurrently with the following embodiments.
  • Novel systems, methods, devices, and software are described to shape and control the data traffic in an ACM system. FIG. 1 is a block diagram illustrating an example satellite communications system 100 configured according to various embodiments of the invention. While a satellite communications system is used to illustrate various aspects of the invention, it is worth noting that certain principles set forth herein are applicable to a variety of other wireless systems, as well. The satellite communications system 100 includes a network 120, such as the Internet, interfaced with a gateway 115 that is configured to communicate with one or more subscriber terminals 130, via a satellite 105.
  • The network 120 may be any type of network and can include, for example, the Internet, an IP network, an intranet, a local- or wide-area network, a virtual private network, the Public Switched Telephone Network (“PSTN”), or any other type of network supporting data communication between devices described herein, in different embodiments. A network 120 may include both wired and wireless connections, including optical links. The network 120 may also transmit information about link conditions for one or more subscriber terminals to the gateway 115. The network may connect the gateway 115 with other gateways (not pictured), which are also in communication with the satellite 105, and which may share information on link conditions and other network metrics.
  • The gateway 115 provides an interface between the network 120 and the subscriber terminal 130. The gateway 115 may be configured to receive data and information directed to one or more subscriber terminals 130, and can format the data and information (e.g., using ACM) for delivery to the respective destination terminal 130 via the satellite 105. Similarly, the gateway 115 may be configured to receive upstream signals from the satellite 105 (e.g., from one or more subscriber terminals) directed to a destination in the network 120, and can format the received signals for transmission along the network 120.
  • A device (not shown) connected to the network 120 may communicate with one or more subscriber terminals through the gateway 115. Data and information, for example IP datagrams, may be sent from a device in the network 120 to the gateway 115. The gateway 115 may format a Medium Access Control (MAC) frame in accordance with a physical layer definition for transmission to the satellite 105. A variety of physical layer transmission modulation and coding techniques may be used with certain embodiments of the invention, including those defined with the DVB-S2 and WiMAX standards. In a number of embodiments, the gateway 115 utilizes ACM in conjunction with one or more of the novel traffic control and shaping techniques described herein to direct traffic to the individual terminals. The gateway 115 may use a broadcast signal, with a modulation and coding (“modcode”) format adapted for each packet to the link conditions of the terminal 130 or set of terminals 130 to which the packet is directed (e.g., to account for the variable service link 150 conditions from the satellite 105 to each respective terminal 130).
  • The gateway 115 may use an antenna 110 to transmit the signals to the satellite 105. In one embodiment, the antenna 110 comprises a parabolic reflector with high directivity in the direction of the satellite and low directivity in other directions. The antenna 110 may be implemented in a variety of alternative configurations. The downstream signals may include, for example, a number of single carrier signals. Each signal carrier signal may be divided (e.g., using TDMA) into a number of virtual channels. The virtual channels may be the same size, or different sizes. In other embodiments, other channelization schemes may be used, such as Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Code Division Multiple Access (CDMA), or any number of hybrid or other schemes known in the art.
  • In one embodiment, a geostationary satellite 105 is configured to receive the signals from the location of antenna 110 and within the frequency band and specific polarization transmitted. The satellite 105 may process the signals received from the gateway 115 and forward the signal from the gateway 115 containing the MAC frame to one or more subscriber terminals 130. In one embodiment, the satellite 105 operates in a multi-beam mode, transmitting a number of narrow beams each directed at a different region of the earth, allowing for frequency re-use. This satellite 105 is configured as a “bent pipe” satellite, wherein the satellite may frequency convert the received carrier signals before retransmitting these signals to their destination, but otherwise perform little or no other processing on the contents of the signals. A variety of physical layer transmission modulation and coding techniques may be used by the satellite 105 in accordance with certain embodiments of the invention, including those defined with the DVB-S2 and WiMAX standards. For other embodiments a number of configurations are possible (e.g., using LEO satellites, or using a mesh network instead of a star network), as evident to those skilled in the art.
  • The service signals 150 transmitted from the satellite 105 may be received by one or more subscriber terminals 130, via the respective subscriber antenna 125. The subscriber terminals 130 may receive the signals from the satellite 105 under very diverse link conditions. In one embodiment, the antenna 125 and terminal 130 together comprise a very small aperture terminal (VSAT). In other embodiments, a variety of other types of antennas 125 may be used at the subscriber terminal 130 to receive a signal. Each of the subscriber terminals 130 may comprise a single user terminal or, alternatively, a hub or router (not pictured) that is coupled to multiple user terminals. Each subscriber terminal 130 may be connected to consumer premises equipment (CPE) 160 comprising, for example computers, local area networks, Internet appliances, wireless networks, etc.
  • In one embodiment, a Multi-Frequency Time-Division Multiple Access (MF-TDMA) scheme is used for upstream links 140, 145, allowing efficient streaming of traffic while maintaining flexibility in allocating capacity among each of the subscriber terminals 130. In this embodiment, a number of frequency channels are allocated which may be fixed, or which may be allocated in a more dynamic fashion. A Time Division Multiple Access (TDMA) scheme is also employed in each frequency channel. In this scheme, each frequency channel may be divided into several timeslots that can be assigned to a connection (i.e., a subscriber terminal 130). In other embodiments, one or more of the upstream links 140, 145 may be configured with other schemes, such as FDMA, OFDMA, CDMA, or any number of hybrid or other schemes known in the art.
  • A subscriber terminal 130 may transmit information related to signal quality to the gateway 115 via the satellite 105. The signal quality may be a measured signal to noise ratio, an estimated signal to noise ratio, a bit error rate, a received power level, or any other communication link quality indicator. The subscriber terminal itself may measure or estimate the signal quality, or it may pass information measured or estimated by other devices. A subscriber terminal may also transmit data and information to a network 120 destination via the satellite 105 and gateway 115. The subscriber terminal 130 transmits the signals via the upstream uplink 145 to the satellite 105 using the antenna 125. A subscriber terminal 130 may transmit the signals according to a variety of physical layer transmission modulation and coding techniques, including those defined with the DVB-S2 and WiMAX standards. In various embodiments, the physical layer techniques may be the same for each of the links 135, 140, 145, 150, or may be different.
  • Referring to FIG. 2A, an example of a modcode table 200 is illustrated in the form of a block diagram. This form of modcode table 200 may, for example, be used by a gateway 115 to determine the modcode to be used for packets destined for a subscriber terminal operating in a given signal quality range. The table contains a column listing a number of modcode formats 205. Each modcode format 205 corresponds to a specified signal quality range 210. Thus, using the signal quality attributed to a destination link for a packet, a signal quality range 210 encompassing the link may be identified, and the appropriate modcode may be selected. For example, if a destination link has a signal quality within Range 7, the modcode QPSK 3/4 may be used. In some embodiments, one or more of the ranges may include a reliability margin (which may be beneficial when channel conditions are changing rapidly, for example). One or more of the ranges may be modified dynamically to adjust this reliability margin as well.
  • In other embodiments, other signal quality indicators may be used, such as a measured signal to noise ratio, an estimated signal to noise ratio, a bit error rate, a received power level, or any other communication link quality indicator. It is also worth noting that a number of other data structures may also be used to relate signal quality ranges to modcodes. In one embodiment, each signal quality is associated with a different packet forwarding queue. In still other embodiments, other information density parameters in addition to modcode changes may be added to further adapt a signal to environmental or other conditions.
  • Turning to FIG. 2B, an example of an address/SNR table 250 is illustrated in the form of a block diagram. This form of address/SNR table 250 may, for example, be used by a gateway 115 to lookup the signal quality 260 of a subscriber terminal 130 to which a packet is destined, based on the destination address 255. The tables in FIGS. 2A and 2B may be embodied on one or more memories, which may be either on or off chip, and may be used in conjunction with one another to correlate a MAC address with a particular modcode format.
  • Although a destination MAC address is used in this example, other mechanisms may be used to identify particular subscriber terminals, including destination VLAN-1D, a Destination Internet Protocol (“DIP”) address, a private addressing ID, any other set of data comprising or otherwise correlated with a destination address. The data address may be parsed from a received data packet after arrival at a device, or it may be received in any other manner known in the art. It is also worth noting that a number of other data structures may also be used to relate an address to signal quality.
  • Once a modcode for a particular packet or packets is identified, for example using the modcode table 200, it may then be encapsulated, coded, mapped and transmitted in a variety of ways, as known in the art. One way to implement ACM is via the DVB-S2 standard, which specifically provides for its use. As noted above, ACM may change the modulation format and Forward Error Correction (FEC) codes (“modcodes”) to best match the current link conditions. This adaptation may occur on a frame by frame basis. The discussion that follows assumes an IP based packet network in the context of a DVB-S2 satellite transmission system, but the concepts may be applied for a variety of systems, including systems implementing DOCSIS or WiMax.
  • Turning to FIG. 3, the framing format 300 for a frame of a DVB-S2 system is set forth to illustrate various aspects of the invention. In one embodiment, each frame is broadcast to all terminals 130, but is only directed at a select subscriber terminal 130 (or small groups of terminals 130). For example, the waveform may be a single carrier waveform transmitted downstream from a gateway 115 to a subscriber terminal 130 in the system 100 of FIG. 1. As noted above, while the DVB-S2 system is used as an example, the principles specified herein are applicable to a range of systems.
  • In this embodiment, a base-band frame 320 is made up of a base-band header 305, a data field 310, and padding 315. Data in the data field may include one or more IP packets encapsulated in a MAC frame, or may include other types of data as well. The data field may include addressing information (e.g., IP address, MAC address, etc.) indicating the terminal or terminals to which the packet will be directed. In some embodiments, IP packets associated with different modcodes may be transmitted in the same base-band frame 320, according to the lower order modcode. The DVB-S2 specification provides that certain frames will be of fixed size regardless of the modcode used (i.e., a normal FEC frame is 64,800 bits, and a shortened FEC frame is 16,200 bits). Therefore, instead of simply padding a frame when there is additional space available and no other remaining packets associated with a current modcode, a data packet (or fragment thereof) associated with a higher order modcode may be inserted into the base-band frame. In one embodiment, the available space is filled with as many additional data packets as will fit without overflow.
  • Interleaving and FEC encoding (e.g., BCH and LDCP) may then be performed on the base-band frame 320 to produce an encoded base-band frame 325, and outer coding parity bits 330 and inner coding parity bits 335 are appended to produce a FEC Frame 340. While, as noted above, the DVB-S2 specification provides that the FEC frame 340 will be of fixed size, in other embodiments, the FEC frame 340 size may vary according to the modcode selected for the frame, to thereby produce, for example, frames of uniform duration in time.
  • The FEC frame 340 is bit mapped to the applicable constellation (e.g., QPSK, 8PSK, 16APSK, 32APSK), to produce a XFEC frame 345 made up of symbols representative of the frame contents. A PL header 350 is added to the XFEC frame 345, together forming the PL frame 365. The PL header 350 is made up of a start of frame (SOF) slot 355 of 26 symbols, and a modcode (MODCOD) slot 360 of 64 symbols specifying the modcode and size (i.e., whether normal or shortened FEC frame). The PL header 350 is encoded. The PL frame 365 is then baseband shaped and quadrature modulated, as well as amplified and upconverted to be transmitted downstream.
  • Referring to FIG. 4, a simplified block diagram illustrates an example of a device 400 configured according to various embodiments of the invention. In one embodiment, the device 400 is the gateway 115 of FIG. 1, transmitting packets downstream with modcodes adapted to the link to which the packets are directed. In other embodiments, the device 400 may be used in any number of different ACM implementations.
  • The device 400 in this embodiment includes a sorting unit 405 and a transmitting unit 410. In some embodiments, the transmitting unit 410 is made up of an encapsulation unit 415, a modulation and coding unit 420, and a transmitter 425. These components (405, 410, 415, 420, and 425) may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art. Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors. Thus, the device 400 may include different types and configurations of memory (not shown), which may be integrated into the hardware or may be one or more separate components.
  • For purposes of discussion, assume that the device 400 is a gateway 115 within the system 100 of FIG. 1. In one embodiment, the system 100 is implemented in a star configuration where each terminal 130 communicates with the device 400, receiving a wide band broadcast signal and searching the waveform for data destined for that terminal 130. Each terminal 130 estimates the SNR of the received signal, although in other embodiments, different signal quality metrics may be used. This information is included in the return path, which may be established via a satellite link or some other means. In other embodiments, the device 400 may receive the link signal quality data from other sources as well. The device 400 then has an SNR estimate for each terminal (e.g., the address/SNR table 250 of FIG. 2B), and may organize this data on one or more memories, which may be implemented in hardware, in a separate computer readable medium, or external to the device 400.
  • Turning now to the packet flow, before being received by the device 400, a data packet may travel through a Class of Service/Quality of Service router (not shown), which may append several fields of information data packet. These fields may include the MAC address of the destination terminal, a counter field, and a time stamp field. Any of this functionality may be integrated into the device, as well.
  • The sorting unit 405 is configured to dynamically assign a different modcode to each data packet after each packet is received by the device. This assignment is based at least in part on a signal quality of a link to which the respective packet is destined. The sorting unit 405 is configured to use the MAC address, in conjunction with the SNR estimate, to identify a modcode to use to communicate with a terminal 130. To do so, the sorting unit 405 may produce or otherwise access a modcode table 200, or other mechanism which correlates certain SNR estimate ranges with different modcodes.
  • A transmitting unit 410, directly or indirectly connected with the sorting unit 405, is configured to transmit the sorted packets according to a defined order of progression, and to produce a broadcast signal output 430. In one embodiment, the defined order of progression comprises transmitting each received data packet associated with a first modcode (perhaps in sequence from oldest to youngest), before incrementing to a next higher order modcode and transmitting each received data packet associated with a next higher order modcode (perhaps in sequence from oldest to youngest), and incrementing accordingly to the highest order modcode. The process is then repeated beginning from the lowest order modcode. Note, however, that the term “defined order of progression” may include any packet forwarding selection or flow control algorithm known in the art. For example, a defined order of progression may encompass any of the number of queueing schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc.
  • In one embodiment, the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and an out of order packet exceeding a threshold age is identified. The interrupt timer interval in one embodiment is 10 mS, but a variety of other intervals are possible. For each 10 mS time interval, several frames may be built, and the real time required to transmit these frames will be tracked. This may be accomplished by totaling the number of symbols required to transmit the physical layer frames. Once enough frames have been created such that more than 10 mS of time is required to transmit them, the timer expires. A number of other timer calculations are possible, as evident to those skilled in the art.
  • In one embodiment, the identified packet is the oldest received packet not yet transmitted (i.e., the threshold age is the age of the second oldest packet). The identified packet is then transmitted, and the defined order of progression may be restarted from the oldest packet. In another embodiment, all packets above a second threshold age are sent before the order of progression is restarted.
  • The device 400 may control other flow modifications when the identified oldest packet is above certain threshold ages. For example, if the identified packet exceeds a first threshold age (e.g., 50 mS), the sorting unit 405 may be further configured to allow data packets associated with a threshold quality or class of service to enter, while blocking others. If the identified packet exceeds a second threshold age (e.g., 80 mS), the sorting unit 405 may be further configured to block all incoming packets until another period of the timer expires. In another embodiment, the transmitting unit 410 is further configured to vary the period of the timer based at least in part on changes in the age of the identified oldest packet (e.g., decreasing the period of the timer if the age of the oldest packet increases). While these changes may be associated with the age of the oldest identified packet (e.g., measured by the difference between timestamp and transmission), other latency and traffic flow measurements may be used to modify these parameters.
  • In another embodiment, the sorting unit 405 is configured to vary a signal quality range associated with one or more modcodes to modify a reliability margin data for packets destined for a link within the varied signal quality range. For example, the sorting unit may be configured to increase the reliability margin when traffic is light, and decrease the reliability margin when traffic is heavy. This adjustment may, for example, be made based on the age of the oldest packet identified at the expiration of the timer (e.g., if T0>60 mS, set margin to 1 dB; if 60 mS>T≧40 mS, set margin to 2 dB; if 40 mS>T0, set margin to 3 dB).
  • In some embodiments, the defined order of progression may include having the sorting unit 405 configured to group data packets associated with different modcodes for encapsulation in one frame to be transmitted according to a lowest order modcode of the different modcodes, the grouping to occur when there are no other remaining data packets that are associated with the lowest order modcode. For example, when there is additional space available in a base-band frame 320 and no other remaining packets are associated with a current modcode, a data packet (or fragment thereof) associated with a next higher order modcode may be inserted into the base-band frame 320.
  • To fill the additional space, a higher order packet may be fragmented, for example, into a first fragment and a second fragment. In such an embodiment, the first fragment may be sized to fill the available space, and transmitted in the first frame according to the lower order modcode. The second fragment may then be transmitted in a following frame according to the higher modcode.
  • In such embodiments, the transmitting unit 410 may include an encapsulation unit 415. The encapsulation unit 415 may be configured to encapsulate in a frame (e.g., a single base-band frame 320) one or more packets associated with a lower order modcode and one or more additional packets associated with a higher order modcode. The transmitting unit 410 also includes a modulation and coding unit 420 configured to encode and map the frame according to the lower order modcode (e.g., to produce XFEC frame 345). A transmitter 425 may baseband shape and quadrature modulate the frame, as well as amplify and upconvert the signal, to produce a broadcast signal output 430.
  • FIG. 5 is a flowchart illustrating a process 500 of implementing adaptive coding and modulation in a broadcast signal. The process may be performed, for example, in whole or in part by the device 400 of FIG. 4. At block 505, a first modcode is associated with a first signal quality range. At block 510, a higher order second modcode is associated with a second signal quality range of better quality.
  • At block 515, a first data packet destined for a first link within the first signal quality range and a second data packet destined for a second link within the second signal quality range arc received. At block 520, the first data packet and at least a part of the second data packet are encapsulated in a single frame. At block 525, the first frame is transmitted in the broadcast signal according to the first modcode.
  • FIG. 6 is a flowchart illustrating a process 600 for controlling the flow of data traffic in a broadcast signal implementing adaptive coding and modulation. The process may be performed, for example, in whole or in part by the device 400 of FIG. 4. At block 605, a modcode is dynamically assigned to each of a number of data packets based on a signal quality of a link to which each respective packet is destined. At block 610, each data packet is associated with a timestamp. At block 615, some of the received data packets are transmitted according to a defined order of progression. At block 620, the defined order of progression is interrupted upon expiration of a timer, and an out of order packet is transmitted with a timestamp exceeding a threshold age.
  • FIG. 7 is a flowchart illustrating a process 700 for controlling the flow of data traffic in a broadcast signal implementing adaptive coding and modulation. The process may be performed, for example, in whole or in part by the device 400 of FIG. 4. At block 705, various modcodes are each associated with different signal quality ranges, the signal quality ranges including a reliability margin. At block 710, a modcode is assigned to each of a number of data packets based on a signal quality of a link to which each respective packet is destined. At block 715, a timestamp is associated with each of the data packets.
  • At block 720, some of the data packets are transmitted according to a defined order of progression, the order providing for data packets assigned to different modcodes to be transmitted in a single frame according to the lower order modcode. At block 725, upon expiration of a timer, the defined order of progression is interrupted to transmit an oldest packet. At block 730, the defined order of progression is restarted from the oldest packet.
  • At block 735, a measure of latency associated with the transmission is determined (e.g., based on the age of the transmitted oldest packet, or using other latency or flow characteristics). At block 740, at least one of the signal quality ranges associated with the modcodes are varied to modify the reliability margin, the varying based at least in part on the latency measure. At block 745, the period of the timer is varied based at least in part on the latency measure. At block 750, only packets with certain class or quality of service characteristics are allowed, while others are blocked, based at least in part on the characteristics of the oldest packet. The process may then be restarted from block 710.
  • Referring next to FIG. 8, a simplified block diagram illustrates an example of a queueing device 800 configured to queue and transmit packets according to their modcode. The queueing device 800, in one embodiment, may be the device 400 described in relation to FIG. 4, implementing adaptive modulation and coding utilizing the queueing process described below.
  • The device 800 in this embodiment includes a queueing unit 805, a number of packet forwarding queues 810, and a transmitting unit 815. These components (805, 810, and 815) may be in communication with one another, and may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art. Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors. The queues 810 may be embodied on one or more memories, which may be either on or off chip.
  • For purposes of discussion, assume that the device 800 is a gateway 115 within the system 100 of FIG. 1. However, note that in other embodiments, the device 800 may be used in any number of different ACM implementations. In one embodiment, the system 100 is implemented in a star configuration where each terminal 130 communicates with the device 800, receiving a wide band broadcast signal and searching the waveform for data destined for that terminal 130. Each terminal 130 may estimate the signal quality of the service link using any one of a variety of metrics, and transmit the estimate to the queueing device via the return path. In other embodiments the device 800 may receive the link signal quality data from other sources as well. The device 800 then has a receive signal estimate for each terminal (e.g., the address/SNR table 250 of FIG. 2B), and may organize this data on one or more memories, which may be implemented in hardware, in a separate computer readable medium, or external to the device 800.
  • Turning now to the packet flow, a data packet from a data source may be received by the queueing device 800. The queueing device 800 includes a number of individual packet forwarding queues 810, each assigned a different modcode and associated with a select one of a number of signal quality ranges. After entering the device, each respective packet is received by a queueing unit 805 configured to place the packet into a select one of the packet forwarding queues 810. The particular queue selected is based on its association with a signal quality range encompassing a signal quality of a link to which the respective packet is destined. To make this assignment, the queueing unit 805 may produce or otherwise access a modcode table 200, or other mechanisms which correlate certain signal quality estimate ranges with different modcodes. By queueing packets as they arrive, the queueing unit 805 is able to order the packets in the queues 810 from oldest to youngest. Thus, the queues 810 may be FIFO buffers, so the packets in each queue are in time order. (It is worth noting that in some embodiments, the sorting unit 405 of FIG. 4 may be implemented as the queueing unit 805 of FIG. 8).
  • A transmitting unit 815, directly or indirectly connected with the packet forwarding queues 810, is configured to transmit the packets according to a defined order of progression, and to produce a broadcast signal output 820. In one embodiment, the defined order of progression comprises transmitting each received data packet in a given forwarding queue associated with a first modcode (e.g., in sequence from oldest to youngest), before incrementing to the queue 810 associated with the next higher order modcode and transmitting each received data packet associated with a next higher order modcode (again, perhaps in sequence from oldest to youngest), and incrementing accordingly to the queue 810 with the highest order modcode. Once the queue with the highest order modcode is emptied, the process is then repeated beginning from the queue 810 associated with the lowest order modcode. Note that in one embodiment, the defined order of progression may provide for transmitting at least one data packet from a first selected queue and a data packet or fragment from a second selected queue in a single frame according to lower order modcode. For example, when there is additional space available in a base-band frame 320 and no other remaining packets are associated with a current modcode, a data packet (or fragment thereof) associated with a next higher order modcode may be inserted into the base-band frame 320. Note, also, that the term “defined order of progression” may include any of a number of queueing schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc.
  • The defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and a packet exceeding a threshold age and from an out of order queue 810 is identified. In one embodiment, the identified packet is the oldest received packet not yet transmitted (i.e., the threshold age is the second oldest packet). The identified packet is then transmitted, and the defined order of progression may be restarted from the transmitted packet. Note that in one embodiment, the defined order of progression may provide for transmitting at least one data packet from the first selected queue and the data packet from the second selected queue in a single frame according to the first modcode
  • Turning to FIG. 9, an alternative embodiment of the queueing device 800 is illustrated, including additional component functionality from that described with respect to FIG. 8. In this embodiment, before being received by the device 400, a data packet may travel from the data source through a Class of Service/Quality of Service router 930, which may append the class or quality of service information field and an address field identifying the destination terminal.
  • From the QoS/CoS Router, a data packet may be transmitted to the queueing device 805. In addition to the functionality described above, the queueing unit 805 in this embodiment may include a timestamp 905 unit, a counter 910, a filtering unit 915, and a margin unit 920. The queueing device 800 may utilize these components to control certain flow modifications. The timestamp 905 unit may be used to append or otherwise associate a timestamp to a packet when it is received by the device, or at other processing stages. The timestamp may, therefore, be used to determine the “age” of given packet. The timestamp may be used by other components of the queueing device 800 to determine latency associated with a particular packet or packets at different stages of processing (i.e., latency from receipt at the device 800 to transmission, latency within the queuing unit, etc.).
  • The queueing unit 805 may make use of the timestamp in a number of ways. For example, consider an interruption of the defined order of progression to identify an out of order packet. If age (determined through use of the timestamp 905 unit) of the identified packet exceeds a first threshold age (e.g., 60 mS), the filtering unit 915 may be configured to allow data packets associated with a threshold quality or class of service to enter, while blocking others. If the identified packet exceeds a second threshold age (e.g., 90 mS), the filtering unit 915 may be further configured to block all incoming packets until another period of the timer expires.
  • In one embodiment, the queueing unit 805 includes a margin unit 920 configured to vary a signal quality range associated with one or more queues. The margin unit 920 may vary the signal quality range of a queue to modify a reliability margin for data packets destined for a link within the varied signal quality range. By way of example, the margin unit 920 may be configured to increase the minimum signal quality of a range when traffic is light, and decrease the minimum signal quality of a range when traffic is heavy. This adjustment may, for example, be made based on the age of the packet identified at the expiration of the timer 925.
  • In one embodiment, the queueing unit utilizes a counter 910 to associate an order with the data packets, perhaps on a per destination address basis. The transmitting unit 815 may be configured to hold transmission of a data packet when the packet is out of the order specified by the counter.
  • As noted above, according to one set of embodiments, the defined order of progression is interrupted upon expiration of a timer, and a packet exceeding a threshold age, and from an out of order queue 810, is identified. The timer may be located on, or off the device. In one embodiment, an on-device timer 925 is located in the transmitting unit 815. The transmitting unit 815 may be configured to vary the period of the timer based at least in part on the latency measure or a data flow measure (e.g., decreasing the period of the timer if the age of packets and the data flow through the device 800 increase). While these changes may be associated with the age of the packet identified from the out of order queue, other latency and traffic flow measurements may be used to modify these parameters (e.g., filtering unit 915 parameters, margin unit 920 parameters, or period of the timer 925).
  • Turning to FIG. 10, a flow diagram illustrates an example decision flow 1000 for a device, such as the queueing device 800 of FIG. 8 or 9. At block 1002, assume that the process begins upon the expiration of a timer, such as the timer 925 in the transmitting unit 820 of FIG. 9. The timer then restarts. In this embodiment, there is a table in which MAC addresses of the destination terminals are associated with the queues 810 (e.g., by using the tables 200, 250). At block 1004, these tables are updated with revised SNR information from the terminals. Incoming data packets are filtered at block 1006 according to blocking rules based on latency measurements, and these rules may, for example, be implemented by the filtering unit 915. At block 1008, allowed packets are placed into respective queues 810, based on the destination terminal SNR and the signal ranges applicable to the queues 810. The queue 810 with the oldest packet, and the age of that packet, are identified at block 1010. These first blocks in FIG. 10 (1002, 1004, 1006, 1008, 1010) may be initiated together at on or about the same time.
  • The reliability margin calculations for each modcode queue 810 may then be revised, at block 1012, based on the age of the oldest packet. Also, the blocking rules may be modified, at block 1014, also based on the age of the oldest packet. These revisions will be implemented, at block 1016, upon the expiration of the timer. In other embodiments, the period of the timer may be modified based on the age of the oldest packet, as well.
  • At block 1018, the oldest packet (or fragment thereof) is moved from the identified queue 810 to the payload portion of a frame, for example, a base-band frame 320 for the DVB-S2 system. At block 1020, a determination is made as to whether the frame is completed (e.g., a determination that there is no available space left in the frame). If the frame is complete, the frame is encapsulated and forwarded to the modulation and coding unit at block 1022, where it is encoded and mapped accordingly. At block 1024, a determination is made whether the frame includes a beginning of a fragment. If so, block 1026 indicates that the next frame will begin with the remaining portion of the fragment to complete the packet (regardless of whether the timer expires in the interim). At block 1028, a determination is made whether the timer has expired. If yes, at block 1048 the process 1000 is restarted, back to block 1002.
  • Returning to block 1020, if the determination is made that the frame is not complete, the frame may continue to be filled. Similarly, if the timer has not expired at block 1028, a new frame may be constructed. In each case, a determination is made at block 1030 regarding whether the last packet from a current queue 810 has been sent. If packets remain in the current queue 810, the process returns to block 1018 to move the oldest packet from the current queue 810 to fill (or begin) the frame. However, if it is determined that no packets remain in the current queue 810, a frame may still be filled or constructed with a packet from a queue associated with a higher order queue.
  • Thus, at block 1032, a determination is made whether all higher order queues are empty. If not, a current queue identifier increments, at block 1034, to the next highest non-empty queue 810, and then returns to block 1018 to move the oldest packet from the newly identified queue 810 to fill (or begin) the frame. When a frame is eventually completed and forwarded to the modulation and coding unit at block 1022, and packets associated with different modcodes are in a single frame, the lowest order modcode associated with the packets of the frame is used. It will be evident to those skilled in the art how the process described may empty queues 810 to construct and fill frames, incrementing to next higher order non-empty queues 810 as current queues 810 are emptied.
  • Returning to block 1032, if it is determined that there are no higher order queues with packets remaining, the frame is padded at block 1036 (e.g., with the padding 315 of a DVB-S2 base-band frame 320). The frame is encapsulated and forwarded to the modulation and coding unit at block 1038, where it is encoded and mapped accordingly. At block 1040, a determination is made whether the timer has expired. If yes, the process 1000 is restarted at block 1048. If the timer has not expired, at block 1042 a determination is made whether all lower order queues are empty. If not, the process decrements, at block 1044, to the lowest order non-empty queue 810, and then returns to block 1018 to move the oldest packet from that queue 810 to begin the next frame, with the process repeating in the manner described above from block 1018.
  • Returning to block 1042, if the determination is that all lower order queues are empty, an all pad frame is built at block 1046. The process returns to block 1038, where the all pad frame is encapsulated and forwarded to the modulation and coding unit, where it is encoded and mapped accordingly, and the process continues from there.
  • FIG. 11 is a flowchart illustrating a process 1100 for controlling the flow of data traffic implementing adaptive coding and modulation using packet forwarding queues. The process may be performed, for example, in whole or in part by the device 800 of FIG. 8 or 9. At block 1105, a different modcode is assigned to each of a number of packet forwarding queues, each queue associated with a different signal quality range. At block 1110, received data packets are each placed into selected queues, the selected queue associated with a signal quality range encompassing the signal quality of a link to which the respective packet is destined. At block 1115, at least some of the data packets are transmitted according to a defined order of progression. At block 1120, the defined order of progression is restarted upon expiration of a timer to identify, and transmit, an out of order packet exceeding a threshold age. In one set of embodiments, this identified packet is the oldest packet remaining in the queues.
  • Turning to FIG. 12, a flowchart is shown which illustrates an alternative process 1200 for controlling the flow of data traffic using packet forwarding queues to implement adaptive coding and modulation. The process may be performed, for example, in whole or in part by the device 800 of FIG. 8 or 9. At block 1205, modcodes are each associated with a signal quality range, the signal quality range including a reliability margin. At block 1210, the modcodes are each assigned to one of a number of packet forwarding queues, each queue thereby associated with a different signal quality range.
  • At block 1215, respective data packets are each placed into selected queues, the selected queue for each packet being the queue associated with a signal quality range encompassing the signal quality of a link to which the respective packet is destined. At block 1220, data packets are transmitted according to a defined order of progression, the order including emptying a queue and incrementing to the next higher order modcode queue, wherein select data packets assigned to different modcodes are transmitted in a single frame according to the lower order modcode. At block 1225, the defined order of progression is interrupted upon the expiration of a timer to identify and transmit the oldest packet in the queues, from an out of order queue. The defined order of progression is then restarted, at block 1230, from the oldest packet and its queue.
  • At block 1235, a measure of latency associated with the oldest packet is determined. At block 1240, at least one of the signal quality ranges associated with the modcodes are varied to modify the reliability margin, based at least in part on the latency measure. The period of the timer is also varied, at block 1245, based at least in part on the latency measure. At block 1250, packets with certain class or quality of service characteristics are allowed to enter the queues while others are blocked, this filtering based at least in part on the characteristics of the oldest packet (e.g., via the latency measure).
  • While FIGS. 8-12 illustrate a set of embodiments in which packet forwarding queues arc used to implement various aspects of the invention, certain principles set forth may be applied using a variety of alternative data structures. Referring next to FIG. 13, a simplified block diagram illustrates an example of a traffic shaping device 1300 configured to utilize a linked list data structure to shape and control data traffic according to modcode in an ACM system. The traffic shaping device 1300, in one embodiment, may be the device 400 described in relation to FIG. 4, implementing adaptive modulation and coding utilizing a linked list in the manner described below.
  • The device 1300 in this embodiment includes a processing unit 1305, buffers 1310, a linked list 1315, and a transmitting unit 1320. These components (1305, 1310, 1315, and 1320) may be in communication with one another, and may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art. Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors. The buffers 1310 and linked list 1315 may be embodied on one or more memories, which may be either on or off chip.
  • For purposes of discussion, assume that the device 1300 is a gateway 115 within the system 100 of FIG. 1. However note that in other embodiments, the device 1300 may be used in any number of different ACM implementations. As noted in regard to other embodiments, each terminal 130 may measure the signal quality of the service link using any one of a variety metrics, and transmit the measurement to the traffic shaping device 1300 via the return path. In other embodiments the device 1300 may receive the link signal quality data from other sources as well. The traffic shaping device 1300 may then have a receive signal measurement from each terminal (e.g., the address/SNR table 250 of FIG. 2B), and may organize this data on one or more memories, which may be implemented in hardware, in a separate computer readable medium, or external to the device 1300.
  • Turning now to the packet flow, before being received by the device 1300, a data packet may travel from a data source through a Class of Service/Quality of Service router (not shown), which may append several fields of information data packet. These fields may include the QoS/CoS information for the packet, address information of the destination terminal, a counter field, and a time stamp field. Any of this functionality may be integrated into the device 1300, as well.
  • Upon being received by the traffic shaping device 1300 from a data source, the processing unit 1305 may store received data packets (and any appended data) in the buffers 1310. The processing unit 1305 also inserts a new element associated with the buffered data packet in a linked list 1315, which will be used to shape the traffic as it is transmitted from the device 1300. In one embodiment, the sorting unit 405 of FIG. 4 is the processing unit 1305 of FIG. 13.
  • The linked list may be structured in a variety of ways, as known in the art, and the following explanation illustrates only a subset of the implementations possible. In one embodiment, the linked list may be characterized as a data structure made up of a sequence of elements, each element containing one (or more) field for data, and also containing two pointers linking the element to the next and previous elements. In one embodiment, the data in each element is made up of a token or other pointer referencing the buffered data packet (and any appended data) which the element represents. In other embodiments, the token or other pointer may reference a table which includes certain portions of the information from the buffered packet and other sources. For example, the token or other pointer may directly or indirectly reference the modcode and address/SNR tables (200, 250) in FIGS. 2A and 2B. There are thus a variety of ways in which the one (or more) data field from an element may be associated with the buffered data packet (and any appended data) which the element represents.
  • As noted, the linked list 1315 may be characterized as a data structure made up of a sequence of elements, each element containing a field (or fields) for data, and also containing pointers linking the element to the next and previous elements. In one embodiment, the linked list is a circularly linked list, where the last element in the list is linked back to the first. For ease in discussing the following embodiment, the “top” of the list will hereinafter be referred to as part of the list holding the element associated with the oldest packet remaining to be forwarded, while the “bottom” of the list will hereinafter be referred to as the part of the list holding the element associated with the newest packet remaining to be forwarded. As data packets are received, their associated elements are inserted into the bottom of the list, to thereby construct the list.
  • Note that while in other embodiments packet forwarding queues may be used to shape and control traffic, a different though related mechanism may be used in the following embodiments. For example, instead of having modcodes related to queues, consider an embodiment wherein each of a number of modcodes is related to signal quality ranges (without also necessarily be related to physical queues). This relation could be embodied on one or more memories, which may be either on or off chip. This relation may, for example, be the table 200 of FIG. 2A. However, there are a variety of ways in which signal qualities ranges may be related to modcodes. Note also that there may more than one range related to each modcode, and the ranges may be of any size.
  • As noted above, when data packets are received by the traffic shaping device 1300, the processing unit 1305 may store received data packets (and any appended data) in the buffers 1310. The processing unit 1305 also inserts a new element associated with the buffered data packet in the linked list 1315. The processing unit 1305 may then identify a signal quality range associated with a given modcode. Identified items in the list will be removed in some embodiments, so that the top of the list will identify the oldest packets to be transmitted, and the linked list will proceed to the bottom in chronological order. The processing unit 1305 will then iterate through the linked list 1315 to identify elements associated with data packets destined for links within the identified signal quality range. Once the bottom of the list is reached, the processing unit 1305 may circle to the top of the linked list 1315, and iterate through to identify elements associated with links within a second signal quality range assigned to the next higher order modcode. This process may be repeated to identify elements associated with packets for incrementing higher modcodes. Once the signal quality range associated with the highest order modcode is emptied, the process is then repeated beginning from the signal quality range associated with the lowest order modcode. This order of progression is merely one example of many, but will be used for much of the discussion below
  • The transmitting unit 1320 is configured to access or otherwise receive the buffered data packets. The transmitting unit 1320 may transmit the packets in an order corresponding to a sequence in which their associated elements are identified, and according to the modcode assigned to the identified signal quality range. In one embodiment, the transmitting unit 410 of FIG. 4 is the transmitting unit 1320 of FIG. 13. Once data is transmitted (or perhaps upon confirmation of receipt), the memory (e.g., buffers 1310) for the transmitted packet may be allocated as available.
  • The processing unit 1305 may be configured to identify packets according to a defined order of progression. Also, the transmitting unit 1320 may be configured to transmit the packets according to the defined order of progression, and to produce a broadcast signal output 1325. In one embodiment, the defined order of progression comprises identifying and transmitting received data packets in a given signal quality range associated with a first modcode (e.g., in sequence from oldest to youngest), before identifying and transmitting each received data packet associated with a next higher order modcode (again, perhaps in sequence from oldest to youngest), and incrementing accordingly to the highest order modcode. Once the packets associated with highest order modcode are identified, the process may then be repeated beginning from the identified packets from the lowest order modcode.
  • Note that in one embodiment, the defined order of progression may provide for transmitting at least one data packet within a first signal quality range assigned a first modcode and a data packet or fragment from a second signal quality range assigned a second modcode in a single frame according the lower order modcode. For example, when there is additional space available in a base-band frame 320 and no other remaining packets are associated with a current modcode, a data packet (or fragment thereof) associated with a next higher order modcode may be inserted into the base-band frame 320. Note, also, that the term “defined order of progression” includes any of a number of schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc.
  • In one embodiment, the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and a packet exceeding a threshold age is identified. In one embodiment, the identified packet is the oldest received packet not yet transmitted (i.e., it is the packet from the top of the list). The identified packet is then transmitted, and the defined order of progression may be restarted from the transmitted packet (i.e., the “current” signal quality range will become the signal quality range of the identified packet, and the iteration through the list will continue).
  • Turning to FIG. 14, an alternative embodiment of the traffic shaping device 1300 is illustrated, including additional component functionality from that described with respect to FIG. 13. In addition to the functionality described above for FIG. 13, the processing unit 805 in this embodiment may include a timestamp 1405, a filtering unit 1410, a margin unit 1415, and a timer 1420. The traffic shaping device 1300 may utilize these components to control certain flow modifications. The timestamp 1405 may be used to append or otherwise associate a time to a packet when it is received by the device, or at other processing stages. The timestamp 1405 may, therefore, be used to determine the “age” of the given packet. The timestamp may be used by other components of the traffic shaping device 1300 to determine latency associated with a particular packet or packets at different stages of processing (i.e., latency from receipt at the device 1300 to transmission, latency within the processing unit 1305, etc.).
  • The processing unit 1305 may make use of a timestamp in a number of ways. For example, consider an interruption of the defined order of progression to identify an out of order packet. If age (determined through use of the timestamp 1405) of the identified packet exceeds a first threshold age (e.g., 70 mS), the filtering unit 1410 may be configured to allow an element to be inserted into the linked list 1315 only if a data packet has a threshold quality or class of service, while blocking others. If the identified packet exceeds a second threshold age (e.g., 120 mS), the filtering unit 1410 may be further configured to prevent any elements from being inserted into the linked list. The processing unit 1305 may be configurable to change these thresholds.
  • In one embodiment, the processing unit 1305 includes a margin unit 1415 configured to dynamically change a signal quality range associated with one or more queues. The margin unit 920 may vary the signal quality range associated with a modcode to modify a reliability margin for data packets destined for a link within the varied signal quality range. By way of example, the margin unit 1415 may be configured to increase the minimum signal quality of a range when traffic is light, and decrease the minimum signal quality of a range when traffic is heavy. This adjustment may, for example, be made based on the age of the packet identified at the expiration of the timer 1420.
  • As noted above, according to one set of embodiments, the defined order of progression is interrupted upon expiration of a timer, and a packet exceeding a threshold age, and from an out of order signal quality range, is identified. The timer may be located on, or off the device. In one embodiment, an on-device timer 1420 is located in the processing unit 1305. The processing unit 1305 may be configured to change the period of the timer based at least in part on the latency measure or a data flow measure (e.g., decreasing the period of the timer if the age of the packets and data flow through the device 1300 increase). While these changes may be associated with the age of the packet identified, other latency and traffic flow measurements may be used to modify the parameters related to reliability margin, block and allow rules, and period of the timer.
  • It is also worth noting that the linked list and buffers may be located in separate areas of memory, or share an area of memory 1425.
  • Turning to FIG. 15A, a block diagram 1500 illustrating a simplified example of an ACM implementation using a linked list is shown. The block diagram illustrates how a linked list 1505 may be used to control the flow of traffic. The linked list 1505 of FIG. 15 may be the linked list 1315 of FIGS. 13 and 14. In this embodiment, the linked list 1505 is a data structure made up of a sequence of elements (or nodes), each element containing one (or more) fields for data, and also containing two pointers linking the element to the next and previous elements. The pointers linking each element to the next and previous elements are shown as links 1515. While the elements 1-25 in FIG. 15A are shown as being adjacent to one another, they may in fact occupy very diverse regions of memory, as is evident to those skilled in the art. In one embodiment, the data in each element is made up of a token or other pointer referencing a buffered data packet (and any appended data) which the element represents. In other embodiments, the token or other pointer may indirectly reference a table which includes certain portions of the information from the buffered packet and other sources. For example, in this embodiment a table 1510 is indirectly connected to linked list 1505, and the table 1510 shows the SNR estimate for the link associated with a variety of MAC addresses.
  • In this embodiment, the linked list 1505 is a circularly linked list, where the last element in the list is linked back to the first. For ease in discussing the following embodiment, the “top” of the list will be referred to as part of the list holding the element associated with the oldest packet remaining to be forwarded, while the “bottom” of the list will be referred to as the part of the list holding the element associated with the newest packet remaining to be forwarded. As data packets are received, their associated elements are inserted into the bottom of the list, to thereby construct the list. As packets are identified for transmission, their associated elements are removed from the list.
  • FIG. 15A illustrates the list at first time (T1). Assume that in this embodiment, a first signal quality range includes SNR “a”, but no other SNRs are in the range. For each element, the device 1300 may identify the MAC address of the element, and then access the table 1510-a to determine if the element is associated with a MAC address in the range. The device 1300 iterates through the linked list 1505-a from elements 1-25, identifying and removing elements 1, 8, 17, and 24, because these elements are associated with SNRs within the range. A second signal quality range associated with the next higher modcode includes SNR “g”, but no other SNRs are in the range. For each remaining element, the device 1300 may identify the MAC address of the element, and then access the table 1510-a to determine if the element is associated with a MAC address in the range. The device 1300 iterates through the linked list 1505, identifying and removing elements 3 and 19, because these elements are associated with SNRs within the second range The packets associated with elements 1, 8, and 17 are transmitted in a first frame according to the modcode assigned to the first signal quality range. However, because there is space in the DVB-S2 base-band frame 320, packets associated with elements 24 and 3 are transmitted in a second frame according to the modcode assigned to the first signal quality range. The packet associated with element 19 are transmitted in a third frame according to the modcode assigned to the second signal quality range.
  • FIG. 15B shows the linked list 1505-b at a second time (T2) after the device has iterated through elements 1-25, then through 2-7, 9-16, and 18-23, at which time the timer expires. As is evident, elements 1, 3, 8, 17, 19, and 24 have been removed from the linked list 1505-b, and new elements 26-28 have been added, and the elements that remain are linked from oldest at the top to newest at the bottom. However, instead of iterating though elements 25-28, the device 1300 will go to the top of the linked list to identify the oldest element (element 2) because of the expiration of the timer. The device will identify the signal quality range of this identified element, and iterate from element 2 down through the list, identifying other elements associated with packets in this range. Also note that with the expiration of the timer, the table 1510-b is updated, and there is a new SNR for MAC address 4. The foregoing example is used only to illustrate a simplified example of how a linked list may be used in various embodiments of the invention.
  • Turning to FIG. 16, a flow diagram illustrates an example decision flow 1600 for a device, such as the traffic shaping device 1300 of FIG. 13 or 14. Assume a linked list, such as the linked list 1505 of FIGS. 15A or 15B, is ordered chronologically with the oldest elements at the top of the list. At block 1002, assume that the process begins upon the expiration of a timer, such as the timer 1420 in the processing unit 1305 of FIG. 1400. The timer then restarts. In this embodiment, different SNR ranges are associated with different modcodes. Also, there is a table in which MAC addresses of the destination terminals are associated SNRs 1510. At block 1604, these tables are updated with revised SNR information from the terminals. Incoming data packets are filtered at block 1606 according to blocking rules based on latency measurement for the device 1300, and these rules may for example be implemented by the filtering unit 1410. At block 1608, allowed packets are associated with elements, and the elements are inserted into the bottom of the linked list. At block 1610, the signal quality range encompassing the signal quality for the link of the data packet associated with the element at the top of the list is identified. These first blocks in FIG. 16 (1602, 1604, 1606, 1608, 1610) may be initiated together at on or about the same time.
  • The reliability margin calculations for each modcode may then be revised, at block 1612, based on the age of the packet at the top of the list (e.g., by varying the signal quality range associated with the modcode). Also, the blocking rules may be modified at block 1614, also based on the age of the packet at the top of the list (i.e., the oldest packet). These revisions will be implemented at block 1616, upon the expiration of the timer. In other embodiments, the period of the timer may be modified based on the age of the oldest packet, as well. Note, also, that in other embodiments, other latency or flow measurements may be used to adjust the reliability margin, filtering rules, or period of the timer.
  • At block 1618, the packet (or fragment thereof) associated with the element from the top of the list is moved from the buffer to the payload portion of a frame, for example, a base-band frame 320 for the DVB-S2 system. The element may then be removed from the top of the list. At block 1620, a determination is made as to whether the frame is completed (e.g., a determination that there is no available space left in the frame). If the frame is complete, the frame is encapsulated and forwarded to the modulation and coding unit at block 1622, where it is encoded and mapped accordingly. At block 1624, a determination is made whether the frame includes a beginning of a fragment. If so, block 1626 indicates that the next frame will begin with the remaining portion of the fragment to complete the packet (regardless of whether timer expires in interim). At block 1628, a determination is made whether the timer has expired. If yes, at block 1650 the process 1600 is restarted, back to block 1602.
  • Returning to block 1620, if the determination is made that the frame is not complete, the frame may continue to be filled. Similarly, if the timer has not expired at block 1628, a new frame may be constructed. In each case, a determination is made at block 1630 regarding whether the last packet from the current signal quality range has been sent. This is accomplished by iterating down through the elements of the linked list and checking whether the SNRs of each associated data packet fall with the current range. If so, the next applicable element down the list is identified at block 1632, and the process returns to block 1618 to move the packet associated with the element from the buffers to fill (or begin) the frame. However, if it is determined that no packets remain in the current signal quality range (i.e., the bottom of the linked list is reached), a frame may still be filled or constructed with a packet from a queue associated with a higher order queue.
  • Thus, at block 1634, a determination is made whether other elements are associated with any signal quality ranges assigned to higher order modcodes are empty. This is accomplished by circling to the top of the list and iterating through the list to determine if there are elements associated with the signal quality range assigned to the next higher modcode, and continuing this circling. If there is an element associated with a higher order modcode, a signal quality range increments, at block 1636, to the signal quality range of that element, and then returns to blocks 1632 and 1634 to identify the element and move the associated packet from the buffer to fill (or begin) the frame. When a frame is eventually completed and forwarded to the modulation and coding unit at block 1622, and packets associated with different modcodes are in a single frame, the lowest order modcode associated with the packets of the frame is used. It will be evident to those skilled in the art how the process described may identify the packets from a signal quality range assigned to a modcode to construct and fill frames, and then circle to the top of a list to identify packets from the signal quality range associated with the next higher modcode.
  • Returning to block 1634, if it is determined that there are no elements associated with higher order modcodes, the frame is padded at block 1638 (e.g., with the padding 315 of a DVB-S2 base-band frame 320). The frame is encapsulated and forwarded to the modulation and coding unit at block 1640, where it is encoded and mapped accordingly. At block 1642, a determination is made whether the timer has expired. If yes, the process 1600 is restarted at block 1650. If the timer has not expired, at block 1644, a determination is made whether any elements associated with packets assigned to lower order modcodes remain in the linked list. This is accomplished by circling to the top of the linked list and iterating through the list to determine if there are elements associated with the signal quality range assigned to the lowest order modcode, and continuing this circling. If such an element is found, the process decrements, at block 1646, to the signal quality range of that element, then returns to blocks 1632 and 1634 to identify the element and move the associated packet from the buffer to begin the frame, with the process moving forward from that point.
  • Returning to block 1644, if a determination is made that no elements associated with packets assigned to lower order modcodes remain, an all pad frame is built at block 1648. The process returns to block 1640, where the all pad frame is encapsulated and forwarded to the modulation and coding unit, where it is encoded and mapped accordingly, and the process continues from there.
  • FIG. 17 is a flowchart illustrating a process 1700 for controlling the flow of data traffic by implementing adaptive coding and modulation using a linked list data structure. The process may be performed, for example, in whole or in part, by the device 1300 of FIG. 13 or 14. At block 1705, each of a number of data packets is associated with a signal quality, the signal quality being a representative signal quality of a link to which the packet is destined. At block 1710, a different modcode is assigned to each of a number of signal quality ranges.
  • At block 1715, a number of elements are inserted into a linked list, each element associated with one of the data packets. At block 1720, the linked list is iterated through to identify elements associated with links within a first signal quality range. At block 1725, data packets are transmitted in an order corresponding to a sequence in which their associated elements are identified, the transmission according to a first modcode assigned to the first signal quality range.
  • Turning to FIG. 18, a flowchart is shown which illustrates an alternative process 1200 for controlling the flow of data traffic using linked list data structures to implement adaptive coding and modulation. The process may be performed, for example, in whole or in part, by the device 1300 of FIG. 13 or 14. At block 1805, different modcodes are assigned to each of a number of signal quality ranges. At block 1810, a number of data packets are associated with a signal quality, the signal quality being a representative signal quality of a link to which each packet is destined.
  • At block 1815, in a linked list connected chronologically from oldest element at the top to newest element at the bottom, a number of elements each associated with one of the data packets are inserted. At block 1820, the linked list is iterated through to identify elements associated with links within a first signal quality range. At block 1825, after circling to the top of the linked list, the linked list is iterated through to identify elements associated with links within a second, next higher signal quality range. At block 1830, data packets are transmitted in an order corresponding to a sequence in which their associated elements are identified, wherein one or more frames are transmitted according to a first modcode assigned to the first signal quality range, and each frame includes a packet from both ranges.
  • At block 1835, upon expiration of a timer, a pointer circles to the top of list to thereby identify the oldest packet in the linked list. The packet may then be transmitted. At block 1840, a measure of latency associated with the oldest packet is determined. At block 1845, at least one of the signal quality ranges associated with the modcodes is changed to modify a reliability margin, based at least in part on the latency measure. At block 1850, the period of the timer is modified based at least in part on the latency measure. At block 1855, only elements associated with packets with certain class or quality of service characteristics are allowed to enter the linked list, while others are blocked, based at least in part on the characteristics of the latency measure.
  • Referring next to FIG. 19, a simplified block diagram illustrates an example of a flow control and traffic shaping device 1900 configured to dynamically change the reliability margins associated with different modcodes in an ACM system. The flow control and traffic shaping device 1900, in one embodiment, may be the device 400 described in relation to FIG. 4, implementing adaptive modulation and coding utilizing a dynamically variable reliability margin.
  • The device 1900 in this embodiment includes a processing unit 1905, a transmitting unit 1910, and a table 200 in which modcodes are assigned to various signal quality ranges. These components (1905, 1910, and 200) may be in communication with one another, and may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (ASICs) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art. Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors. The modcode/signal quality range table 200 may be embodied on one or more memories, which may be either on or off chip.
  • For purposes of discussion, assume that the device 1900 is a gateway 115 within the system 100 of FIG. 1. However, note that in other embodiments, the device 1300 may be used in any number of different ACM implementations. As noted in regard to other embodiments, each terminal 130 may measure the signal quality of the service link using any one of a variety of metrics, and transmit the measurement to the flow control and traffic shaping device 1900 via the return path. In other embodiments, the device 1900 may receive the link signal quality data from other sources as well. The device 1900 may then have receive signal quality metrics for each receiving terminal (e.g., the address/SNR table 250 of FIG. 2B), and may organize this data on one or more memories.
  • The processing unit 1905 is configured to assign a different modcode to each data packet after the packet is received by the device. This assignment is based at least in part on a signal quality of a link to which the respective packet is destined. The processing unit 1905 is configured to use a destination, in conjunction with the signal quality estimate, to identify a modcode to use to communicate with a terminal 130. To do so, the processing unit 1905 accesses a modcode table 200, or other mechanisms which correlate certain signal quality ranges with different modcodes.
  • Additionally, the processing unit 1905 in this embodiment is configured to dynamically change a signal quality range associated with one or more modcodes. The processing unit 1905 may change or otherwise vary the signal quality range associated with a modcode to modify a reliability margin for data packets destined for a link within that signal quality range. By way of example, the processing unit 1905 may be configured to increase the minimum signal quality of a particular range when traffic is light, and decrease the minimum signal quality of a particular range when traffic is heavy. The processing unit 1905 in this embodiment may also possess the functionality of the margin units (920, 1415) described in other embodiments.
  • Turning briefly to FIG. 20 to describe further the scope of this terminology, a linear representation of a range of SNR values 2000 is illustrated. The reliability margin 2005 for each of a number of modcodes is shown, as well. The lower limit 2010 of the Es/No value for a particular modcode is shown as the point Rn in FIG. 20. The lower limit 2010 is a somewhat arbitrary characterization, as it may be calculated in a number of different ways. For purposes of this discussion, it may include any identified, requisite, or otherwise suggested boundary for the lower limit for an Es/No value of a particular modcode. The implemented lower limit 2015 of an Es/No value is shown as well, as points Mn in FIG. 20, and is the lower limit 2010 plus a reliability margin for a particular modcode. A reliability margin 2005 is, therefore, the difference between a lower limit 2010 and an implemented lower limit 2015, and may include any environmental, weather, implementation, or other margin.
  • In various embodiments of the invention, the reliability margin for one or more modcodes may be varied dynamically. Consider, for purposes of example, modcode2 2020. Consider first a period of relatively low traffic, and thus low latency. In such an environment, there may be excess capacity available, and thus the reliability margin 2015 may be increased (e.g., to 4 dB) without impacting latency or flow. This way, the reliability margin may be dynamically increased as traffic lightens. However, if there is a sudden burst of significant traffic through the device 1900, the flow demands on the device 1900 may be increased. Thus, the reliability margin 2015 may be dynamically decreased as traffic increases, either incrementally (e.g., 4 dB, to 3 dB, to 2 dB, to 1 dB, to 0.5 dB), or otherwise. A number of factors (latency, flow, anticipated traffic, etc.) may be used to dynamically control a reliability margin, as will be discussed in further detail below. In one embodiment, the reliability margin 2015 is zero. In another embodiment, the reliability margin is fixed, and the signal quality ranges may vary only with changes in weather or other environmental conditions.
  • Returning to FIG. 19, the processing unit 1905 may perform other functions in addition to dynamically adjusting the signal quality range associated with different modcodes. For example, the processing unit 1905 may identify packets for transmission based on modified signal quality ranges, and according to a defined order of progression. The transmitting unit 1910 may transmit packets according to the defined order of progression, and produce a broadcast signal output 1915. In one embodiment, the defined order of progression entails transmitting each received data packet in a given modified signal quality range assigned to a first modcode (e.g., in sequence from oldest to youngest), before incrementing to the next higher order modcode and transmitting each received data packet in a modified signal range associated with a next higher order modcode (again, perhaps in sequence from oldest to youngest), and incrementing accordingly to the highest order modcode. Once the highest order modcode is emptied, the process is then repeated beginning from a modified signal quality range associated with the lowest order modcode. Note that in one embodiment, the defined order of progression may provide for transmitting at least one data packet from a first modified signal quality range and a data packet or fragment from a second modified signal quality range according to the lower order modcode. Note, also, that the term “defined order of progression” may include any of a number of packet forwarding schemes that may order and format packets for forwarding based on modcode, destination address, order received, age, etc., or perhaps randomly.
  • In one embodiment, the defined order of progression is interrupted upon expiration of a timer (hereinafter “interrupt timer”), and a packet exceeding a threshold age, and from an out of order signal quality range, is identified and transmitted. The identified packet in one embodiment is the oldest received packet not yet transmitted (i.e., the threshold age is the second oldest packet). The defined order of progression may be restarted from the transmitted packet.
  • The age of the out of order packet may be utilized in a variety of ways to modify the control of packets through the device 1900. Moreover, other latency and flow measurements may be made by the processing unit 1905 and the transmitting unit 1910. The delay at the device 1900 associated with certain functions and components, or groups of functions and components, may be measured. This type of latency measurement may occur for the out of order packet, or select groups of other packets. The latency measurement may, for example, simply be a count of those packets transmitted that are over some threshold age. A number of latency and packet flow measurements are known in art, and any may be used herein.
  • In addition to on-device latency measurements, external devices may provide additional data, whether locally or from the network. For example, a network operations center (NOC) may transmit certain latency statistics or flow information to a device. A NOC may also provide information on a future change in traffic flow. A variety of network and testing tools are known in the art that may provide flow statistics, latency measurements, and other network information to a device 1900.
  • The processing unit 1905 may use the latency information, flow statistics, and additional network information described above to dynamically change a signal quality range associated with a given modcode and thereby to modify the associated reliability margin. In one embodiment, the reliability margin may be adjusted based on the age of the identified out of order packet, for example: if T0>90 mS, set reliability margin to 0.5 dB; if 90 mS>T0≧60 mS, set reliability margin to 1 dB; and if 60 mS>T0, set margin to 2 dB. Other thresholds may be established to modify signal quality ranges (i.e., to change the reliability margin) based on the other latency information, flow statistics, and additional network information described above.
  • The processing unit 1305 may make use of the latency information, flow statistics, and additional network information described above in a number of other ways. It may use all the received information, or only selected aspects of the received information. By way of example, in addition to modifying the reliability margin, filtering rules for blocking or allowing certain packets may be changed to account for the latency information, flow statistics, and/or additional network information described above. For example, in periods of higher traffic, QoS/CoS priority filtering rules may be implemented. Also, the period of the timer may be modified based on the latency information, flow statistics, and/or additional network information described above. Thus, the period may be decreased when latency increases, to more regularly jump to the oldest remaining packets.
  • FIG. 21 is a flowchart illustrating a process 2100 for controlling the flow of data traffic by implementing adaptive coding and modulation using a dynamic reliability margin. The process may be performed, for example, in whole or in part, by the device 1900 of FIG. 19. At block 2105, a different modcode is assigned to each of a number signal quality ranges. At block 2110, one or more of the signal quality ranges are dynamically varied to modify a reliability margin for delivery of data packets destined for a link with a signal quality within the range.
  • FIG. 22 is a flowchart illustrating an alternative process 2200 for controlling the flow of data traffic by dynamically modifying certain factors in an ACM system. The process may be performed, for example, in whole or in part by the device 1900 of FIG. 19. At block 2205, a different modcode is assigned to each of a number of signal quality ranges. At block 2210, data packets are transmitted in a defined order of progression, at least a subset is transmitted according to the modcode assigned to their destination link. At block 2215, a timer expires, and an out of order packet exceeding a threshold age is identified at block 2220, thereby interrupting the defined order of progression.
  • At block 2225, transmission of data packets is restarted in a defined order of progression from the identified out of order packet. In parallel with block 2225, a range of latency and flow measurements may be made or received at block 2245. For example, the age of the out of order packet may be determined at block 2230, while in other embodiments, other latency measurements associated with the packet may be made as well. At block 2235, other latency factors attributed to a flow or the device 1900 may be measured, and additional flow statistics may be compiled or analyzed. Also, network data may be received at block 2240.
  • This range of latency and flow measurements 2245 may be used, in whole or in part, to calculate a modification to one or more parameters from a group of traffic shaping and flow control parameters 2265. At block 2250, the reliability margin attributable to one or more modcodes may be changed in light of the latency and flow measurements 2245. At block 2255, the period for the timer may be changed in light of the latency and flow measurements 2245. At block 2260, the filtering rules related to blocking or selective blocking based on QoS/CoS may be changed in light of the latency and flow measurements 2245.
  • At block 2270, upon the next expiration of the timer, the modifications to one or more parameters from a group of traffic shaping and flow control parameters 2265 are implemented. At block 2275, transmission of data packets is restarted in a defined order of progression with the implemented changes.
  • It should again be noted that the methods, systems and devices discussed above are intended merely to be exemplary in nature. It must be stressed that various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that in alternative embodiments, the methods may be performed in an order different than that described, and that various steps may be added, omitted or combined. Also, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Also, it should be emphasized that technology evolves and, thus, many of the elements are exemplary in nature and should not be interpreted to limit the scope of the invention.
  • Specific details are given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the embodiments.
  • Also, it is noted that the embodiments may be described as a process which is depicted as a flowchart or a flow diagram. Although they may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed, but could have additional steps not included in the figure.
  • Moreover, as disclosed herein, the term “memory” may represent one or more devices or components thereof for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices or other machine readable mediums for storing information. The term “computer-readable medium” includes, but is not limited to, portable or fixed storage devices, optical storage devices, wireless channels, a sim card, other smart cards, and various other mediums capable of storing, containing or carrying instructions or data.
  • Furthermore, embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine readable medium such as a storage medium. Processors may perform the necessary tasks.
  • Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. For example, the above elements may merely be a component of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of steps may be required before the above elements are considered. Accordingly, the above description should not be taken as limiting the scope of the invention, which is defined in the following claims.

Claims (26)

1.-19. (canceled)
20. A method of controlling the flow of data traffic for a broadcast signal implementing adaptive coding and modulation, the method comprising:
dynamically assigning a modcode of a plurality of modcodes to each of a plurality of data packets based at least in part on a signal quality of a link on which each respective packet is destined;
associating a timestamp with each of the plurality of data packets;
transmitting a subset of the plurality of data packets according to a defined order of progression; and
interrupting the defined order of progression upon expiration of a timer to transmit an out of order packet with a timestamp exceeding a first threshold age, wherein the out of order packet comprises one of the plurality of packets not included in the subset.
21. The method of claim 20, wherein the first threshold age comprises the timestamp of the second oldest of the plurality of data packets not included in the subset.
22. The method of claim 20, further comprising:
blocking additional data packets when the out of order packet exceeds a second threshold age.
23. The method of claim 22, further comprising:
allowing only data packets associated with a threshold quality or class of service to enter while blocking the additional packets.
24. The method of claim 20, further comprising:
restarting the defined order of progression from the out of order packet.
25. The method of claim 20, further comprising:
varying the period of timer based at least in part on a delay associated with transmitting from the packet forwarding queues.
26. The method of claim 20, wherein the transmitting according to the defined order of progression comprises:
transmitting each data packet associated with a first modcode of the plurality of modcodes; and
incrementing to a next higher order second modcode of the plurality of modcodes to transmit a data packet associated with an oldest timestamp of the plurality of data packets associated with the second modcode.
27. The method of claim 26, wherein the transmitting according to the defined order of progression further comprises:
transmitting at least one data packet associated with a first modcode and the data packet associated with the second modcode in a single frame according the first modcode.
28. The method of claim 28, wherein the transmitting according to the defined order of progression further comprises:
determining a length of a prospective pad for the at least one data packet associated with a first modcode;
determining that no data packet associated with the first modcode remains to fill the prospective pad; and
filling the prospective pad with the data packet associated with the second modcode.
29. The method of claim 20, further comprising:
utilizing a counter to associate an order with the plurality of data packets; and
holding transmission of a data packet of the plurality of data packets when the packet is out of the order specified by the counter.
30. The method of claim 20, further comprising:
varying a signal quality range associated with one or more of the plurality of modcodes to modify a reliability margin for at least a subset of the plurality of data packets destined for a link within the varied signal quality range.
31. The method of claim 20, wherein the transmitting according to the defined order of progression comprises:
fragmenting an internet protocol data packet of the plurality of data packets into first fragment and second fragment, each fragment associated with a first modcode of the plurality of modcodes;
transmitting the first fragment according to a second modcode of the plurality of modcodes; and
transmitting the second fragment according to the first modcode, the first modcode of higher order than the second modcode.
32. The method of claim 31, wherein the first fragment is sized to fill a length of prospective pad for a frame to be transmitted according to the second modcode.
33. The method of claim 20, wherein the dynamically assigning the modcode step comprises:
placing selected data packets of the plurality of data packet into selective ones of a plurality of packet forwarding queues each associated with different signal quality ranges.
34. The method of claim 20, further comprising:
inserting, into a linked list, a plurality of elements each corresponding to one or more of the plurality of data packets and an associated signal quality; and
iterating through the linked list to identify a set of data packets for encapsulation and transmission based at least in part on a signal quality associated with each element of the linked list.
35. The method of claim 20, wherein the adaptive coding and modulation is implemented in accordance with a DVB-S2 standard.
36. The method of claim 20, wherein the signal quality comprises at least one of a signal to noise ratio, an estimated signal to noise ratio, a bit error rate, a receive power level, and another communication link quality indicator.
37. A device for controlling the flow of data traffic for a broadcast signal implementing adaptive coding and modulation, the device comprising:
a sorting unit configured to dynamically assign a different modcode to each of a plurality of packets based at least in part on a signal quality of a link on which each respective packet is to be received;
a transmitting unit, coupled with the sorting unit, and configured to:
transmit a subset of the plurality of packets according to a defined order of progression; and
interrupt the defined order of progression upon expiration of a timer to transmit an out of order packet exceeding a threshold age, wherein the out of order packet comprises one of the plurality of packets not included in the subset.
38. The device of claim 37, wherein,
the sorting unit is further configured to block additional data packets when the out of order packet exceeds a second threshold age.
39. The device of claim 38, wherein,
the sorting unit is further configured to allow data packets associated with a threshold quality or class of service to enter.
40. The device of claim 37, wherein,
the transmitting unit is further configured to restarting the defined order of progression from the out of order packet.
41. The device of claim 37, wherein,
the transmitting unit is further configured to varying the period of the timer based at least in part on a latency associated with transmitting from the packet forwarding queues.
42. The device of claim 37, wherein,
the transmitting unit is further configured to:
transmit each data packet associated with a first modcode of the plurality of modcodes before incrementing to a next higher order second modcode of the plurality of modcodes; and
transmit a data packet with an oldest timestamp associated with the second modcode.
43. The device of claim 42, wherein,
the transmitting unit is further configured to transmit at least one data packet associated with the first modcode and the data packet associated with the second modcode in a single frame according to the first modcode.
44. The device of claim 37, wherein,
the sorting unit is configured to vary a signal quality range associated with one or more of the plurality of modcodes to modify a reliability margin for at least a subset of the plurality of data packets destined for a link within the varied signal quality range.
US12/695,236 2005-10-28 2010-01-28 Adaptive coding and modulation for broadband data transmission Active 2027-10-16 US8358657B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/695,236 US8358657B2 (en) 2005-10-28 2010-01-28 Adaptive coding and modulation for broadband data transmission

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US73112205P 2005-10-28 2005-10-28
US11/554,206 US7680040B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation for broadband data transmission
US12/695,236 US8358657B2 (en) 2005-10-28 2010-01-28 Adaptive coding and modulation for broadband data transmission

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/554,206 Division US7680040B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation for broadband data transmission

Publications (2)

Publication Number Publication Date
US20100128678A1 true US20100128678A1 (en) 2010-05-27
US8358657B2 US8358657B2 (en) 2013-01-22

Family

ID=37806694

Family Applications (7)

Application Number Title Priority Date Filing Date
US11/554,206 Active 2028-06-06 US7680040B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation for broadband data transmission
US11/554,263 Active 2028-02-06 US7689162B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation flow control and traffic shaping systems and methods
US11/554,226 Active 2027-09-09 US7684425B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation queuing methods and devices
US11/554,244 Active 2028-04-17 US7675842B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation using linked list data structures
US12/690,572 Active US8072873B2 (en) 2005-10-28 2010-01-20 Adaptive coding and modulation using linked list data structures
US12/695,236 Active 2027-10-16 US8358657B2 (en) 2005-10-28 2010-01-28 Adaptive coding and modulation for broadband data transmission
US12/706,351 Abandoned US20100172234A1 (en) 2005-10-28 2010-02-16 Adaptive coding and modulation flow control and traffic shaping systems and methods

Family Applications Before (5)

Application Number Title Priority Date Filing Date
US11/554,206 Active 2028-06-06 US7680040B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation for broadband data transmission
US11/554,263 Active 2028-02-06 US7689162B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation flow control and traffic shaping systems and methods
US11/554,226 Active 2027-09-09 US7684425B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation queuing methods and devices
US11/554,244 Active 2028-04-17 US7675842B2 (en) 2005-10-28 2006-10-30 Adaptive coding and modulation using linked list data structures
US12/690,572 Active US8072873B2 (en) 2005-10-28 2010-01-20 Adaptive coding and modulation using linked list data structures

Family Applications After (1)

Application Number Title Priority Date Filing Date
US12/706,351 Abandoned US20100172234A1 (en) 2005-10-28 2010-02-16 Adaptive coding and modulation flow control and traffic shaping systems and methods

Country Status (8)

Country Link
US (7) US7680040B2 (en)
EP (2) EP3567768A1 (en)
CA (1) CA2627067C (en)
DK (1) DK1949584T3 (en)
ES (1) ES2726017T3 (en)
IL (5) IL191047A (en)
PL (1) PL1949584T3 (en)
WO (1) WO2007051079A2 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100118768A1 (en) * 2005-10-28 2010-05-13 Viasat, Inc. Adaptive coding and modulation using linked list data structures
CN111373668A (en) * 2017-09-29 2020-07-03 星网有限责任公司 Radio system using nodes with high gain antennas
US11206079B2 (en) 2017-12-11 2021-12-21 Star Mesh LLC Data transmission systems and methods using satellite-to-satellite radio links
US11855745B2 (en) 2016-08-25 2023-12-26 Star Mesh LLC Radio system using satellites
US11870543B2 (en) 2020-05-18 2024-01-09 Star Mesh LLC Data transmission systems and methods for low earth orbit satellite communications

Families Citing this family (107)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040162637A1 (en) 2002-07-25 2004-08-19 Yulun Wang Medical tele-robotic system with a master remote station with an arbitrator
US7813836B2 (en) 2003-12-09 2010-10-12 Intouch Technologies, Inc. Protocol for a remotely controlled videoconferencing robot
US8351468B2 (en) 2004-04-05 2013-01-08 Broadcom Corporation Method and apparatus for downloading content using channel bonding
JP2007533263A (en) * 2004-04-12 2007-11-15 ザ・ディレクティービー・グループ・インコーポレイテッド Shift channel characteristics to mitigate co-channel interference
US8213553B2 (en) * 2004-04-12 2012-07-03 The Directv Group, Inc. Method and apparatus for identifying co-channel interference
US7161988B2 (en) 2004-04-12 2007-01-09 The Directv Group, Inc. Method and apparatus for minimizing co-channel interference
US8077963B2 (en) 2004-07-13 2011-12-13 Yulun Wang Mobile robot with a head-based movement mapping scheme
EP1807951B1 (en) * 2004-10-29 2019-04-10 Avago Technologies International Sales Pte. Limited Hierarchical flow-level multi-channel communication
US9198728B2 (en) 2005-09-30 2015-12-01 Intouch Technologies, Inc. Multi-camera mobile teleconferencing platform
US7986624B2 (en) * 2005-10-28 2011-07-26 Viasat, Inc. Quality of service enhancements for adaptive coding and modulation
JP4985641B2 (en) * 2006-02-16 2012-07-25 日本電気株式会社 Quality degradation location estimation apparatus, quality degradation location estimation method, and quality degradation location estimation program
DE102006021864A1 (en) * 2006-05-09 2007-11-15 Deutsches Zentrum für Luft- und Raumfahrt e.V. Method for transmitting data packets in a broadband satellite radio channel
DE102006025037B3 (en) 2006-05-26 2007-09-13 Deutsches Zentrum für Luft- und Raumfahrt e.V. Resource assignment providing method for use in interactive satellite radio network multimedia system, involves computing burst-time table that takes information by using static or semi-dynamic resources assignment manager
US8849679B2 (en) 2006-06-15 2014-09-30 Intouch Technologies, Inc. Remote controlled robot system that provides medical images
WO2008024056A1 (en) * 2006-08-21 2008-02-28 Telefonaktiebolaget L M Ericsson (Publ) Method and arrangement for adapting transmission of encoded media
US7929568B2 (en) * 2006-08-25 2011-04-19 Gilat Satellite Networks, Inc. Packing data over an adaptive rate link
US8171380B2 (en) 2006-10-10 2012-05-01 Marvell World Trade Ltd. Adaptive systems and methods for storing and retrieving data to and from memory cells
KR100886903B1 (en) * 2006-12-06 2009-03-09 한국전자통신연구원 Method and system for a effective adaptive coding and modulation in satellite communication system
US8843592B2 (en) 2006-12-20 2014-09-23 Omx Technology Ab System and method for adaptive information dissemination
US8565337B2 (en) * 2007-02-07 2013-10-22 Valens Semiconductor Ltd. Devices for transmitting digital video and data over the same wires
WO2008129509A1 (en) 2007-04-23 2008-10-30 Shiron Satellite Communications (1996) Ltd. Method and apparatus for compensation for weather-based attenuation in a satellite link
US7664143B2 (en) * 2007-05-01 2010-02-16 Harris Corporation Communications system using adaptive baseband injected pilot carrier symbols and related method
US9160783B2 (en) 2007-05-09 2015-10-13 Intouch Technologies, Inc. Robot system that operates through a network firewall
MX2009012361A (en) * 2007-05-16 2009-12-01 Thomson Licensing Apparatus and method for encoding and decoding signals.
WO2008149304A2 (en) * 2007-06-05 2008-12-11 Koninklijke Philips Electronics, N.V. Apparatus and method for performing transmission rate adaptation in wireless systems
US8068435B2 (en) * 2007-08-03 2011-11-29 Viasat, Inc. Rate adaptive modem
EP2186216B1 (en) 2007-08-09 2018-10-24 ViaSat, Inc. Virtual gateway redundancy
US9414110B2 (en) 2007-10-15 2016-08-09 Thomson Licensing Preamble for a digital television system
CN101828397A (en) * 2007-10-15 2010-09-08 汤姆森特许公司 Apparatus and method for encoding and decoding signals
US7936707B2 (en) 2007-10-26 2011-05-03 Harris Corporation Satellite communication bandwidth cross layer allocation system and related methods
EP2061167A3 (en) * 2007-11-19 2013-07-31 Gilat Satellite Networks, Ltd. Channel estimation for Digital Video Broadcasting via Satellite (DVB-S2)
US10875182B2 (en) 2008-03-20 2020-12-29 Teladoc Health, Inc. Remote presence system mounted to operating room hardware
US8179418B2 (en) 2008-04-14 2012-05-15 Intouch Technologies, Inc. Robotic based health care system
US8170241B2 (en) 2008-04-17 2012-05-01 Intouch Technologies, Inc. Mobile tele-presence system with a microphone system
US8693946B2 (en) 2008-04-22 2014-04-08 Elbit Systems Land and C41—Tadiran Ltd. Method and apparatus for compensation for weather-based attenuation in a satellite link
WO2009130701A1 (en) * 2008-04-22 2009-10-29 Shiron Satellite Communications (1996) Ltd. Method and apparatus for compensation for weather-based attenuation in a satellite link
US8010705B1 (en) 2008-06-04 2011-08-30 Viasat, Inc. Methods and systems for utilizing delta coding in acceleration proxy servers
US9193065B2 (en) 2008-07-10 2015-11-24 Intouch Technologies, Inc. Docking system for a tele-presence robot
US9842192B2 (en) 2008-07-11 2017-12-12 Intouch Technologies, Inc. Tele-presence robot system with multi-cast features
US8068423B2 (en) * 2008-09-09 2011-11-29 Ericsson Television, Inc Packet scheduling system for digital video broadcasting
US8340819B2 (en) 2008-09-18 2012-12-25 Intouch Technologies, Inc. Mobile videoconferencing robot system with network adaptive driving
US8996165B2 (en) 2008-10-21 2015-03-31 Intouch Technologies, Inc. Telepresence robot with a camera boom
US8411798B2 (en) * 2008-11-05 2013-04-02 Viasat, Inc. Reducing receiver power dissipation
WO2010059740A2 (en) * 2008-11-18 2010-05-27 Viasat, Inc. Improved mobile satellite communication
US8463435B2 (en) 2008-11-25 2013-06-11 Intouch Technologies, Inc. Server connectivity control for tele-presence robot
US9138891B2 (en) 2008-11-25 2015-09-22 Intouch Technologies, Inc. Server connectivity control for tele-presence robot
US9369516B2 (en) 2009-01-13 2016-06-14 Viasat, Inc. Deltacasting
US8849680B2 (en) 2009-01-29 2014-09-30 Intouch Technologies, Inc. Documentation through a remote presence robot
US8565249B2 (en) * 2009-02-10 2013-10-22 Telefonaktiebolaget L M Ericsson (Publ) Queue management system and methods
CN101800616B (en) * 2009-02-10 2012-11-21 富士通株式会社 Data relay device, communication device and method
WO2010104927A2 (en) 2009-03-10 2010-09-16 Viasat, Inc. Internet protocol broadcasting
WO2010121215A1 (en) 2009-04-17 2010-10-21 Viasat, Inc. Layer-2 extension services
US9276663B2 (en) 2009-04-17 2016-03-01 Viasat, Inc. Layer-2 connectivity from switch to access node/gateway
WO2010121217A1 (en) 2009-04-17 2010-10-21 Viasat, Inc. Mobility across satellite beams using l2 connectivity
US8897920B2 (en) 2009-04-17 2014-11-25 Intouch Technologies, Inc. Tele-presence robot system with software modularity, projector and laser pointer
WO2010121214A1 (en) 2009-04-17 2010-10-21 Viasat, Inc. Layer-2 connectivity from switch to access node/gateway
WO2010148211A1 (en) * 2009-06-17 2010-12-23 Viasat, Inc. Adaptive coding and modulation (acm) packet fetch and clustering
US11399153B2 (en) 2009-08-26 2022-07-26 Teladoc Health, Inc. Portable telepresence apparatus
US8384755B2 (en) 2009-08-26 2013-02-26 Intouch Technologies, Inc. Portable remote presence robot
US8516253B1 (en) 2010-01-18 2013-08-20 Viasat, Inc. Self-keyed protection of anticipatory content
US11154981B2 (en) 2010-02-04 2021-10-26 Teladoc Health, Inc. Robot user interface for telepresence robot system
US8670017B2 (en) 2010-03-04 2014-03-11 Intouch Technologies, Inc. Remote presence system including a cart that supports a robot face and an overhead camera
US8984048B1 (en) 2010-04-18 2015-03-17 Viasat, Inc. Selective prefetch scanning
US10343283B2 (en) 2010-05-24 2019-07-09 Intouch Technologies, Inc. Telepresence robot system that can be accessed by a cellular phone
US10808882B2 (en) 2010-05-26 2020-10-20 Intouch Technologies, Inc. Tele-robotic system with a robot face placed on a chair
US8660132B2 (en) * 2010-06-28 2014-02-25 Avaya Inc. Control plane packet processing and latency control
JP5581867B2 (en) 2010-07-15 2014-09-03 富士通株式会社 Wireless communication apparatus and data allocation method
US9264664B2 (en) * 2010-12-03 2016-02-16 Intouch Technologies, Inc. Systems and methods for dynamic bandwidth allocation
JP5905031B2 (en) 2011-01-28 2016-04-20 インタッチ テクノロジーズ インコーポレイテッド Interfacing with mobile telepresence robot
US9323250B2 (en) 2011-01-28 2016-04-26 Intouch Technologies, Inc. Time-dependent navigation of telepresence robots
CN102130954A (en) * 2011-03-17 2011-07-20 华为技术有限公司 Method and device for transmitting data resources
US9912718B1 (en) 2011-04-11 2018-03-06 Viasat, Inc. Progressive prefetching
US9037638B1 (en) 2011-04-11 2015-05-19 Viasat, Inc. Assisted browsing using hinting functionality
US9456050B1 (en) 2011-04-11 2016-09-27 Viasat, Inc. Browser optimization through user history analysis
US9106607B1 (en) 2011-04-11 2015-08-11 Viasat, Inc. Browser based feedback for optimized web browsing
US10769739B2 (en) 2011-04-25 2020-09-08 Intouch Technologies, Inc. Systems and methods for management of information among medical providers and facilities
US9098611B2 (en) 2012-11-26 2015-08-04 Intouch Technologies, Inc. Enhanced video interaction for a user interface of a telepresence network
US20140139616A1 (en) 2012-01-27 2014-05-22 Intouch Technologies, Inc. Enhanced Diagnostics for a Telepresence Robot
US9125147B2 (en) * 2011-05-25 2015-09-01 Alcatel Lucent System and method for providing communication services
US8897302B2 (en) 2011-06-14 2014-11-25 Viasat, Inc. Transport protocol for anticipatory content
US10136165B2 (en) * 2011-09-14 2018-11-20 Mobitv, Inc. Distributed scalable encoder resources for live streams
US9516524B2 (en) * 2011-10-25 2016-12-06 Mediatek, Inc. Transmitter assisted quality of service measurement
US9407355B1 (en) 2011-10-25 2016-08-02 Viasat Inc. Opportunistic content delivery using delta coding
US8836751B2 (en) 2011-11-08 2014-09-16 Intouch Technologies, Inc. Tele-presence system with a user interface that displays different communication links
US9251313B2 (en) 2012-04-11 2016-02-02 Intouch Technologies, Inc. Systems and methods for visualizing and managing telepresence devices in healthcare networks
US8902278B2 (en) 2012-04-11 2014-12-02 Intouch Technologies, Inc. Systems and methods for visualizing and managing telepresence devices in healthcare networks
EP2852475A4 (en) 2012-05-22 2016-01-20 Intouch Technologies Inc Social behavior rules for a medical telepresence robot
US9361021B2 (en) 2012-05-22 2016-06-07 Irobot Corporation Graphical user interfaces including touchpad driving interfaces for telemedicine devices
US8432808B1 (en) 2012-06-15 2013-04-30 Viasat Inc. Opportunistically delayed delivery in a satellite network
US9306640B2 (en) * 2012-09-07 2016-04-05 Qualcomm Incorporated Selecting a modulation and coding scheme for beamformed communication
US9172495B1 (en) 2013-07-01 2015-10-27 Sprint Communications Company L.P. Dynamic modulation change while generating a MAC PDU in a LTE protocol wireless network
US9735859B1 (en) * 2013-11-27 2017-08-15 Vt Idirect, Inc. Method and apparatus for distributing addresses of communication devices within a satellite network
US10855797B2 (en) 2014-06-03 2020-12-01 Viasat, Inc. Server-machine-driven hint generation for improved web page loading using client-machine-driven feedback
US9893800B2 (en) * 2015-03-20 2018-02-13 Qualcomm Incorporated Method and apparatus for spectral efficient data transmission in satellite systems
BR112018001923A2 (en) * 2015-07-31 2018-09-25 Viasat, Inc. satellite system, satellite constellation system, system for programming switching, method for programmed connectivity switching on a satellite of a multisatellite constellation, method for programming connectivity switching in a satellite communications system that has a multisatellite constellation
EP3859567A1 (en) 2015-10-20 2021-08-04 ViaSat Inc. Hint model updating using automated browsing clusters
US10069465B2 (en) 2016-04-21 2018-09-04 Communications & Power Industries Llc Amplifier control system
FR3052945B1 (en) 2016-06-16 2018-07-06 Thales Sa IMPROVED SATELLITE DATA TRANSMISSION METHOD AT VERY HIGH SPEED
CN106101012B (en) * 2016-07-06 2020-05-12 广州海格通信集团股份有限公司 Satellite IP gateway protocol adaptation method
US10312996B2 (en) * 2016-09-30 2019-06-04 Hughes Network Systems, Llc Systems and methods for using adaptive coding and modulation in a regenerative satellite communication system
US10270704B2 (en) * 2016-11-10 2019-04-23 Microsoft Technology Licensing, Llc. Throttling output with ongoing input
EP3361651A1 (en) * 2017-02-10 2018-08-15 Airbus Defence and Space Limited Ultra-low latency telecommunications system
US11862302B2 (en) 2017-04-24 2024-01-02 Teladoc Health, Inc. Automated transcription and documentation of tele-health encounters
US10483007B2 (en) 2017-07-25 2019-11-19 Intouch Technologies, Inc. Modular telehealth cart with thermal imaging and touch screen user interface
US11636944B2 (en) 2017-08-25 2023-04-25 Teladoc Health, Inc. Connectivity infrastructure for a telehealth platform
US10617299B2 (en) 2018-04-27 2020-04-14 Intouch Technologies, Inc. Telehealth cart that supports a removable tablet with seamless audio/video switching
US11223418B2 (en) * 2019-12-31 2022-01-11 Hughes Network Systems, Llc Multi-band satellite terminal estimating a second band based on first band link conditions

Citations (59)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4819629A (en) * 1986-10-28 1989-04-11 Siemens Aktiengesellschaft Method and apparatus for delivering aerosol to the airways and/or lungs of a patient
US5517495A (en) * 1994-12-06 1996-05-14 At&T Corp. Fair prioritized scheduling in an input-buffered switch
US5586550A (en) * 1995-08-31 1996-12-24 Fluid Propulsion Technologies, Inc. Apparatus and methods for the delivery of therapeutic liquids to the respiratory system
US5914946A (en) * 1996-11-08 1999-06-22 Lucent Technologies Inc. TDM-based fixed wireless loop system
US5917900A (en) * 1997-02-07 1999-06-29 Mci Communications Corporation Remote data gateway
US5991812A (en) * 1997-01-24 1999-11-23 Controlnet, Inc. Methods and apparatus for fair queuing over a network
US6122280A (en) * 1995-08-11 2000-09-19 Matsushita Electric Industrial Co. Ltd. Packet output device and packet output method
US6138012A (en) * 1997-08-04 2000-10-24 Motorola, Inc. Method and apparatus for reducing signal blocking in a satellite communication system
US20020036992A1 (en) * 2000-03-13 2002-03-28 Krishna Balachandran Method and apparatus for packet size dependent link adaptation for wireless packet
US6385462B1 (en) * 2000-05-26 2002-05-07 Motorola, Inc. Method and system for criterion based adaptive power allocation in a communication system with selective determination of modulation and coding
US20020097750A1 (en) * 2000-07-28 2002-07-25 Lakshminarayanan Gunaseelan System, server, and method for variable bit rate multimedia streaming
US20020118666A1 (en) * 2000-11-15 2002-08-29 Stanwood Kenneth L. Framing for an adaptive modulation communication system
US20020131441A1 (en) * 2000-04-07 2002-09-19 Trachewsky Jason Alexander Method of determining an end of a transmitted frame in a frame-based communications network
US20020150115A1 (en) * 2001-03-09 2002-10-17 O. Raif Onvural Time based packet scheduling and sorting system
US20020183020A1 (en) * 2001-06-05 2002-12-05 Nortel Networks Limited Adaptive coding and modulation
US6519636B2 (en) * 1998-10-28 2003-02-11 International Business Machines Corporation Efficient classification, manipulation, and control of network transmissions by associating network flows with rule based functions
US20030045307A1 (en) * 2001-08-24 2003-03-06 Eli Arviv Asymmetric adaptive modulation in a wireless communication system
US20030054816A1 (en) * 2001-09-20 2003-03-20 Krebs Lawrence W. Methods and apparatus for mitigating rain fading over satcom links via information throughput adaptation
US20030110435A1 (en) * 2001-12-10 2003-06-12 Ar Card Adaptive multi-mode harq system and method
US20030121030A1 (en) * 2001-12-21 2003-06-26 Christopher Koob Method for implementing dual link list structure to enable fast link-list pointer updates
US20030126536A1 (en) * 2001-12-28 2003-07-03 Sridhar Gollamudi Delay sensitive adapative quality control loop for rate adaptation
US20030176161A1 (en) * 2002-03-15 2003-09-18 Broadcom Corporation Downstream adaptive modulation in DOCSIS based communications systems
US20040001493A1 (en) * 2002-06-26 2004-01-01 Cloonan Thomas J. Method and apparatus for queuing data flows
US6701129B1 (en) * 2000-09-27 2004-03-02 Nortel Networks Limited Receiver based adaptive modulation scheme
US20040064790A1 (en) * 2002-09-30 2004-04-01 Brother Kogyo Kabushiki Kaisha Communication system, communication terminal, system control program product and terminal control program product
US20040085976A1 (en) * 2002-11-06 2004-05-06 Mark Dale Downstream time domian based adaptive modulation for DOCSIS based applications
US20040100941A1 (en) * 2002-11-20 2004-05-27 Kwang Jae Lim Adaptive packet transmission method for transmitting packets in multibeam satellite communication system
US20040120474A1 (en) * 2001-04-17 2004-06-24 Jussi Lopponen Packet mode speech communication
US6765921B1 (en) * 2000-06-28 2004-07-20 Nortel Networks Limited Communications network
US20040141601A1 (en) * 2003-01-22 2004-07-22 Yigang Cai Credit reservation transactions in a prepaid electronic commerce system
US6804211B1 (en) * 1999-08-03 2004-10-12 Wi-Lan Inc. Frame structure for an adaptive modulation wireless communication system
US20040203992A1 (en) * 2002-04-25 2004-10-14 Sang-Boh Yun Power controllable wireless mobile communications system of adaptive modulation and coding scheme and method therefor
US20040208121A1 (en) * 2003-04-21 2004-10-21 Broadcom Corporation Method and system for adaptive modulation scheduling
US20040247122A1 (en) * 2003-04-24 2004-12-09 General Instrument Corporation Processing multiple encrypted transport streams
US6845095B2 (en) * 2001-04-27 2005-01-18 Telefonaktiebolaget Lm Ericsson (Publ) Efficient header handling involving GSM/EDGE radio access networks
US20050013593A1 (en) * 2003-03-28 2005-01-20 Samsung Electronics Co., Ltd. Method and apparatus for guaranteeing seamless reproduction of a plurality of data streams
US6865393B1 (en) * 2000-03-03 2005-03-08 Motorola, Inc. Method and system for excess resource distribution in a communication system
US20050060760A1 (en) * 1999-12-03 2005-03-17 Broadcom Corporation Interspersed training for turbo coded modulation
US6885857B1 (en) * 1998-01-07 2005-04-26 Verisign, Inc. System and method for real-time bundled telecommunications account processing and billing
US20050138521A1 (en) * 2003-11-03 2005-06-23 Hiroshi Suzuki FEC (Forward Error Correction) decoder with dynamic parameters
US20050147034A1 (en) * 2003-08-25 2005-07-07 Yongdong Zhao Method of performing weighted round-robin queue scheduling using a dynamic link list and structure for implementing same
US20050213587A1 (en) * 2004-03-26 2005-09-29 Samsung Electronics Co., Ltd. Apparatus and method for scheduling packets in a wireless communication system
US6990529B2 (en) * 2000-02-24 2006-01-24 Zarlink Semiconductor V.N., Inc. Unified algorithm for frame scheduling and buffer management in differentiated services networks
US20060067325A1 (en) * 2004-09-30 2006-03-30 Michael Kounavis Method and apparatus for sorting packets in packet schedulers using a connected trie data structure
US20060104299A1 (en) * 2004-10-22 2006-05-18 Vazquez Castro Maria A Method and a device for scheduling and sending data packets from a common sender to a plurality of users sharing a common transmission channel
US20060126576A1 (en) * 2004-12-09 2006-06-15 Mark Dale Partial mesh communication in hub based system
US7126996B2 (en) * 2001-12-28 2006-10-24 Motorola, Inc. Adaptive transmission method
US20070096788A1 (en) * 2005-10-28 2007-05-03 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US20070110098A1 (en) * 2003-12-09 2007-05-17 Viasat, Inc. Method For Channel Congestion Management
US20070206525A1 (en) * 1999-08-16 2007-09-06 Viasat, Inc. Adaptive Data Rate Control for Narrowcast Networks
US7289456B2 (en) * 2002-04-08 2007-10-30 Telcordia Technologies, Inc. Determining and provisioning paths within a network of communication elements
US20070271388A1 (en) * 2006-05-22 2007-11-22 Microsoft Corporation Server-side media stream manipulation for emulation of media playback functions
US7319669B1 (en) * 2002-11-22 2008-01-15 Qlogic, Corporation Method and system for controlling packet flow in networks
US20080144493A1 (en) * 2004-06-30 2008-06-19 Chi-Hsiang Yeh Method of interference management for interference/collision prevention/avoidance and spatial reuse enhancement
US20080212517A1 (en) * 2005-10-28 2008-09-04 Viasat, Inc. Quality of service enhancements for adaptive coding and modulation
US7426687B1 (en) * 2001-01-04 2008-09-16 Omniture, Inc. Automatic linking of documents
US20090028187A1 (en) * 2003-01-28 2009-01-29 Broadcom Corporation Upstream adaptive modulation in a communications system
US20090052323A1 (en) * 2005-03-21 2009-02-26 Dirk Breynaert Managing Traffic in a Satellite Transmission System
US7567504B2 (en) * 2003-06-30 2009-07-28 Microsoft Corporation Network load balancing with traffic routing

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU5550694A (en) * 1992-11-06 1994-06-08 Pericle Communications Company Adaptive data rate modem
US5588550A (en) * 1995-10-10 1996-12-31 Pepsico, Inc. Compartmented container including closure with access to individual compartments
FR2783431B1 (en) 1998-09-23 2001-02-02 System Assistance Medical NEBULIZER FOR DELIVERING A FOG TO A PATIENT AND METHOD FOR OPERATING SUCH A NEBULIZER
US6885657B1 (en) 1998-11-30 2005-04-26 Broadcom Corporation Network telephony system
FI20040389A0 (en) * 2004-03-11 2004-03-11 Nokia Corp Method and apparatus for controlling transmission of data volumes
US7209612B2 (en) * 2004-03-24 2007-04-24 Enablence Inc. Two-stage optical bi-directional transceiver
TWI290817B (en) * 2006-06-12 2007-12-01 Power Quotient Int Co Ltd Business card type storage device
US20090218187A1 (en) * 2007-02-08 2009-09-03 Kyong-Soo Chung Tilted Push-Pull Wheeled Luggage with a Removable Front Swingable Wheel with an Elongated Neck for the Removable Front Swingable Wheel

Patent Citations (74)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4819629A (en) * 1986-10-28 1989-04-11 Siemens Aktiengesellschaft Method and apparatus for delivering aerosol to the airways and/or lungs of a patient
US5517495A (en) * 1994-12-06 1996-05-14 At&T Corp. Fair prioritized scheduling in an input-buffered switch
US6122280A (en) * 1995-08-11 2000-09-19 Matsushita Electric Industrial Co. Ltd. Packet output device and packet output method
US5586550A (en) * 1995-08-31 1996-12-24 Fluid Propulsion Technologies, Inc. Apparatus and methods for the delivery of therapeutic liquids to the respiratory system
US5914946A (en) * 1996-11-08 1999-06-22 Lucent Technologies Inc. TDM-based fixed wireless loop system
US5991812A (en) * 1997-01-24 1999-11-23 Controlnet, Inc. Methods and apparatus for fair queuing over a network
US5917900A (en) * 1997-02-07 1999-06-29 Mci Communications Corporation Remote data gateway
US6138012A (en) * 1997-08-04 2000-10-24 Motorola, Inc. Method and apparatus for reducing signal blocking in a satellite communication system
US6885857B1 (en) * 1998-01-07 2005-04-26 Verisign, Inc. System and method for real-time bundled telecommunications account processing and billing
US6519636B2 (en) * 1998-10-28 2003-02-11 International Business Machines Corporation Efficient classification, manipulation, and control of network transmissions by associating network flows with rule based functions
US6804211B1 (en) * 1999-08-03 2004-10-12 Wi-Lan Inc. Frame structure for an adaptive modulation wireless communication system
US20050058098A1 (en) * 1999-08-03 2005-03-17 Klein Israel Jay Frame structure for an adaptive modulation wireless communication system
US20070206525A1 (en) * 1999-08-16 2007-09-06 Viasat, Inc. Adaptive Data Rate Control for Narrowcast Networks
US20050060760A1 (en) * 1999-12-03 2005-03-17 Broadcom Corporation Interspersed training for turbo coded modulation
US6990529B2 (en) * 2000-02-24 2006-01-24 Zarlink Semiconductor V.N., Inc. Unified algorithm for frame scheduling and buffer management in differentiated services networks
US6865393B1 (en) * 2000-03-03 2005-03-08 Motorola, Inc. Method and system for excess resource distribution in a communication system
US20020036992A1 (en) * 2000-03-13 2002-03-28 Krishna Balachandran Method and apparatus for packet size dependent link adaptation for wireless packet
US20020131441A1 (en) * 2000-04-07 2002-09-19 Trachewsky Jason Alexander Method of determining an end of a transmitted frame in a frame-based communications network
US20030206559A1 (en) * 2000-04-07 2003-11-06 Trachewsky Jason Alexander Method of determining a start of a transmitted frame in a frame-based communications network
US6385462B1 (en) * 2000-05-26 2002-05-07 Motorola, Inc. Method and system for criterion based adaptive power allocation in a communication system with selective determination of modulation and coding
US6765921B1 (en) * 2000-06-28 2004-07-20 Nortel Networks Limited Communications network
US20020097750A1 (en) * 2000-07-28 2002-07-25 Lakshminarayanan Gunaseelan System, server, and method for variable bit rate multimedia streaming
US6701129B1 (en) * 2000-09-27 2004-03-02 Nortel Networks Limited Receiver based adaptive modulation scheme
US20020118666A1 (en) * 2000-11-15 2002-08-29 Stanwood Kenneth L. Framing for an adaptive modulation communication system
US7426687B1 (en) * 2001-01-04 2008-09-16 Omniture, Inc. Automatic linking of documents
US20020150115A1 (en) * 2001-03-09 2002-10-17 O. Raif Onvural Time based packet scheduling and sorting system
US20040120474A1 (en) * 2001-04-17 2004-06-24 Jussi Lopponen Packet mode speech communication
US6845095B2 (en) * 2001-04-27 2005-01-18 Telefonaktiebolaget Lm Ericsson (Publ) Efficient header handling involving GSM/EDGE radio access networks
US7043210B2 (en) * 2001-06-05 2006-05-09 Nortel Networks Limited Adaptive coding and modulation
US20020183020A1 (en) * 2001-06-05 2002-12-05 Nortel Networks Limited Adaptive coding and modulation
US20030045307A1 (en) * 2001-08-24 2003-03-06 Eli Arviv Asymmetric adaptive modulation in a wireless communication system
US20030054816A1 (en) * 2001-09-20 2003-03-20 Krebs Lawrence W. Methods and apparatus for mitigating rain fading over satcom links via information throughput adaptation
US20030110435A1 (en) * 2001-12-10 2003-06-12 Ar Card Adaptive multi-mode harq system and method
US20030121030A1 (en) * 2001-12-21 2003-06-26 Christopher Koob Method for implementing dual link list structure to enable fast link-list pointer updates
US7126996B2 (en) * 2001-12-28 2006-10-24 Motorola, Inc. Adaptive transmission method
US20030126536A1 (en) * 2001-12-28 2003-07-03 Sridhar Gollamudi Delay sensitive adapative quality control loop for rate adaptation
US20030176161A1 (en) * 2002-03-15 2003-09-18 Broadcom Corporation Downstream adaptive modulation in DOCSIS based communications systems
US7289456B2 (en) * 2002-04-08 2007-10-30 Telcordia Technologies, Inc. Determining and provisioning paths within a network of communication elements
US20040203992A1 (en) * 2002-04-25 2004-10-14 Sang-Boh Yun Power controllable wireless mobile communications system of adaptive modulation and coding scheme and method therefor
US20040001493A1 (en) * 2002-06-26 2004-01-01 Cloonan Thomas J. Method and apparatus for queuing data flows
US20040064790A1 (en) * 2002-09-30 2004-04-01 Brother Kogyo Kabushiki Kaisha Communication system, communication terminal, system control program product and terminal control program product
US20040085976A1 (en) * 2002-11-06 2004-05-06 Mark Dale Downstream time domian based adaptive modulation for DOCSIS based applications
US20040100941A1 (en) * 2002-11-20 2004-05-27 Kwang Jae Lim Adaptive packet transmission method for transmitting packets in multibeam satellite communication system
US7319669B1 (en) * 2002-11-22 2008-01-15 Qlogic, Corporation Method and system for controlling packet flow in networks
US20040141601A1 (en) * 2003-01-22 2004-07-22 Yigang Cai Credit reservation transactions in a prepaid electronic commerce system
US20090028187A1 (en) * 2003-01-28 2009-01-29 Broadcom Corporation Upstream adaptive modulation in a communications system
US20050013593A1 (en) * 2003-03-28 2005-01-20 Samsung Electronics Co., Ltd. Method and apparatus for guaranteeing seamless reproduction of a plurality of data streams
US20040208121A1 (en) * 2003-04-21 2004-10-21 Broadcom Corporation Method and system for adaptive modulation scheduling
US20040247122A1 (en) * 2003-04-24 2004-12-09 General Instrument Corporation Processing multiple encrypted transport streams
US7567504B2 (en) * 2003-06-30 2009-07-28 Microsoft Corporation Network load balancing with traffic routing
US20050147034A1 (en) * 2003-08-25 2005-07-07 Yongdong Zhao Method of performing weighted round-robin queue scheduling using a dynamic link list and structure for implementing same
US20050138521A1 (en) * 2003-11-03 2005-06-23 Hiroshi Suzuki FEC (Forward Error Correction) decoder with dynamic parameters
US20070110098A1 (en) * 2003-12-09 2007-05-17 Viasat, Inc. Method For Channel Congestion Management
US20050213587A1 (en) * 2004-03-26 2005-09-29 Samsung Electronics Co., Ltd. Apparatus and method for scheduling packets in a wireless communication system
US20080144493A1 (en) * 2004-06-30 2008-06-19 Chi-Hsiang Yeh Method of interference management for interference/collision prevention/avoidance and spatial reuse enhancement
US20060067325A1 (en) * 2004-09-30 2006-03-30 Michael Kounavis Method and apparatus for sorting packets in packet schedulers using a connected trie data structure
US20060104299A1 (en) * 2004-10-22 2006-05-18 Vazquez Castro Maria A Method and a device for scheduling and sending data packets from a common sender to a plurality of users sharing a common transmission channel
US7450602B2 (en) * 2004-10-22 2008-11-11 Agence Spatiale Europeenne Method and a device for scheduling and sending data packets from a common sender to a plurality of users sharing a common transmission channel
US20060126576A1 (en) * 2004-12-09 2006-06-15 Mark Dale Partial mesh communication in hub based system
US20090052323A1 (en) * 2005-03-21 2009-02-26 Dirk Breynaert Managing Traffic in a Satellite Transmission System
US7675842B2 (en) * 2005-10-28 2010-03-09 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US20080212517A1 (en) * 2005-10-28 2008-09-04 Viasat, Inc. Quality of service enhancements for adaptive coding and modulation
US8072873B2 (en) * 2005-10-28 2011-12-06 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US20070097852A1 (en) * 2005-10-28 2007-05-03 Viasat, Inc. Adaptive coding and modulation flow control and traffic shaping systems and methods
US20070116151A1 (en) * 2005-10-28 2007-05-24 Viasat, Inc. Adaptive coding and modulation for broadband data transmission
US20070116152A1 (en) * 2005-10-28 2007-05-24 Viasat, Inc. Adaptive coding and modulation queuing methods and devices
US20070096788A1 (en) * 2005-10-28 2007-05-03 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US7680040B2 (en) * 2005-10-28 2010-03-16 Viasat, Inc. Adaptive coding and modulation for broadband data transmission
US20100118768A1 (en) * 2005-10-28 2010-05-13 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US7689162B2 (en) * 2005-10-28 2010-03-30 Viasat, Inc. Adaptive coding and modulation flow control and traffic shaping systems and methods
US7684425B2 (en) * 2005-10-28 2010-03-23 Viasat, Inc. Adaptive coding and modulation queuing methods and devices
US20100172234A1 (en) * 2005-10-28 2010-07-08 Viasat, Inc. Adaptive coding and modulation flow control and traffic shaping systems and methods
US7986624B2 (en) * 2005-10-28 2011-07-26 Viasat, Inc. Quality of service enhancements for adaptive coding and modulation
US20070271388A1 (en) * 2006-05-22 2007-11-22 Microsoft Corporation Server-side media stream manipulation for emulation of media playback functions

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100118768A1 (en) * 2005-10-28 2010-05-13 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US20100172234A1 (en) * 2005-10-28 2010-07-08 Viasat, Inc. Adaptive coding and modulation flow control and traffic shaping systems and methods
US8072873B2 (en) 2005-10-28 2011-12-06 Viasat, Inc. Adaptive coding and modulation using linked list data structures
US11855745B2 (en) 2016-08-25 2023-12-26 Star Mesh LLC Radio system using satellites
CN111373668A (en) * 2017-09-29 2020-07-03 星网有限责任公司 Radio system using nodes with high gain antennas
US11356921B2 (en) 2017-09-29 2022-06-07 Star Mesh LLC Radio system using nodes with high gain antennas
US11832160B2 (en) 2017-09-29 2023-11-28 Star Mesh LLC Radio system using nodes with high gain antennas
US11206079B2 (en) 2017-12-11 2021-12-21 Star Mesh LLC Data transmission systems and methods using satellite-to-satellite radio links
US11870543B2 (en) 2020-05-18 2024-01-09 Star Mesh LLC Data transmission systems and methods for low earth orbit satellite communications

Also Published As

Publication number Publication date
US20070116152A1 (en) 2007-05-24
US20070096788A1 (en) 2007-05-03
US20070116151A1 (en) 2007-05-24
IL220289A0 (en) 2012-07-31
EP1949584B1 (en) 2019-03-06
IL220292A0 (en) 2012-07-31
US7680040B2 (en) 2010-03-16
IL191047A0 (en) 2008-12-29
US7684425B2 (en) 2010-03-23
CA2627067C (en) 2010-02-16
WO2007051079A3 (en) 2007-07-19
US8358657B2 (en) 2013-01-22
US20070097852A1 (en) 2007-05-03
ES2726017T3 (en) 2019-10-01
US8072873B2 (en) 2011-12-06
US7675842B2 (en) 2010-03-09
IL220292A (en) 2013-03-24
WO2007051079A2 (en) 2007-05-03
EP1949584A2 (en) 2008-07-30
US7689162B2 (en) 2010-03-30
IL220289A (en) 2013-03-24
IL191047A (en) 2012-08-30
IL220291A0 (en) 2012-07-31
IL220291A (en) 2013-03-24
US20100172234A1 (en) 2010-07-08
IL220288A0 (en) 2012-07-31
CA2627067A1 (en) 2007-05-03
DK1949584T3 (en) 2019-06-03
US20100118768A1 (en) 2010-05-13
PL1949584T3 (en) 2019-09-30
EP3567768A1 (en) 2019-11-13
IL220288A (en) 2013-03-24

Similar Documents

Publication Publication Date Title
US8358657B2 (en) Adaptive coding and modulation for broadband data transmission
US7986624B2 (en) Quality of service enhancements for adaptive coding and modulation
US8159992B2 (en) Routing paths onboard satellite with reference terminal functionality
US8243651B2 (en) Aggregate rate modem
WO2010054395A2 (en) Dynamic frequency assignment in a multi-beam system
US8576859B2 (en) ACM packet fetch and clustering
MXPA05001248A (en) Automatic retransmit request protocol for channels with time-varying capacity.
KR100822513B1 (en) Method and apparatus for packet size dependent link adaptation for wireless packet
US11777596B2 (en) Optimisation for data transmission

Legal Events

Date Code Title Description
AS Assignment

Owner name: VIASAT, INC., CALIFORNIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:THESLING, WILLIAM H.;REEL/FRAME:023863/0428

Effective date: 20061031

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

AS Assignment

Owner name: UNION BANK, N.A., CALIFORNIA

Free format text: SECURITY AGREEMENT;ASSIGNOR:VIASAT, INC.;REEL/FRAME:028184/0152

Effective date: 20120509

STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

AS Assignment

Owner name: WILMINGTON TRUST, NATIONAL ASSOCIATION, AS COLLATE

Free format text: SECURITY INTEREST;ASSIGNOR:VIASAT, INC.;REEL/FRAME:048715/0589

Effective date: 20190327

Owner name: WILMINGTON TRUST, NATIONAL ASSOCIATION, AS COLLATERAL TRUSTEE, MINNESOTA

Free format text: SECURITY INTEREST;ASSIGNOR:VIASAT, INC.;REEL/FRAME:048715/0589

Effective date: 20190327

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8

AS Assignment

Owner name: BANK OF AMERICA, N.A., NORTH CAROLINA

Free format text: SECURITY AGREEMENT;ASSIGNOR:VIASAT, INC.;REEL/FRAME:059332/0558

Effective date: 20220304

AS Assignment

Owner name: BANK OF AMERICA, N.A., AS AGENT, NORTH CAROLINA

Free format text: SECURITY AGREEMENT;ASSIGNOR:VIASAT, INC.;REEL/FRAME:063822/0446

Effective date: 20230530